1 [Aristotle, see Volume 1, Lessons 7 and 8.]

2 [Theophrastus, see Volume 1, Lesson 9.]

3 [Pliny the Elder, see Volume 1, Lesson 13.]

4 [Aelian of Praeneste, see Volume 1, Lesson 15.]

5 [Athenaeus on Naucratis, see Volume 1, Lesson 14, note 27.]

6 [According to the Census of Marine Life, about 8.7 million (give or take 1.3 million) is the latest estimated total number of species on Earth, with 6.5 million species on land and 2.2 million in the oceans. The number is based on an innovative, validated analytical technique that dramatically narrows the range of previous estimates. For more or the number of species, see Mora et al. 2011; for another estimate, see Locey & Lennon 2016.]

7 [Tournefort, see Volume 2, Lesson 13, note 31.]

8 [This is Linnaeus’s system of taxonomy, now known as binomial nomenclature, first used consistently in the tenth edition of his Systema naturae (1758-1759), which is considered the starting point of zoological nomenclature; see Volume 1, Lesson 7, note 34; Volume 3, Lesson 5, note 3.]

9 [Stamen, the male reproductive part of a flower, which, in all but a few flowering plants (angiosperms) consists of a long slender stalk, the filament, with a two-lobed anther at the tip. The anther consists of four saclike structures that produce pollen for pollination.]

10 [Linnaeus’s famous “sexual system,” which he published in 1735: Methodus plantarum sexualis, in Systema naturae, sive Regna tria naturae systematice proposita per classes, ordines, genera, et species. Leiden: Theodor Haak, 1735, 7 leaves, 1 vol. in-folio; see also Methodus sexualis sistens genera plantarum secundum mares et feminas in classes et ordines redacta, Leiden: Conrad Wishoff, 1737, 23 p.]

11 [Pistil, the female reproductive part of a flower, which, centrally located, typically consists of a swollen base, the ovary, which contains the potential seeds, or ovules; a stalk, or style, arising from the ovary; and a pollen-receptive tip, the stigma, variously shaped and often sticky. In pollination, compatible pollen grains land on the stigma and then germinate, forming a pollen tube. The pollen tube grows down through the tissue of the style to deposit sperm for the fertilization of the ovules in the ovary.]

12 [Calyx, the collective term for the sepals of a flower; sepals, in turn, are the parts of a flowering plant that typically function to protect the flower in bud, and often as support for the petals when in bloom.]

13 [Corolla, the collective term for the petals of a flower; petals, in turn, are modified leaves that surround the reproductive parts of flowers. Often brightly colored or unusually shaped to attract pollinators, petals are usually accompanied by another set of special leaves called sepals, that collectively form the calyx and lie just beneath the corolla.]

14 [Umbellifers, members of the Umbelliferae (or Apiaceae), commonly known as the carrot or parsley family, aromatic plants with hollow stems, including a host of well-known species, such as angelica, anise, caraway, carrot, celery, coriander, cilantro, cumin, dill, fennel, hemlock, Queen Anne’s lace, parsley, parsnip, and sea holly.]

15 [Bindweeds, members of the Convolvulaceae, the bindweed family or morning glory family, including about 60 genera and more than 1,650 species, many of which are invasive weeds but others cultivated for their attractive flowers, while some are globally threatened.]

16 [Pentandria, in the Linnaean artificial system: the fifth class of plants, comprising those having hermaphrodite flowers with five stamens; it may also refer to an order characterized by flowers with five stamens in any of certain other classes.]

17 [Philosopher’s stone, or Stone of the Philosophers, a legendary alchemical substance capable of turning base metals such as mercury into gold or silver. It is also called the elixir of life, useful for rejuvenation and for achieving immortality; for many centuries, it was the most sought goal in alchemy; the central symbol of the mystical terminology of alchemy, symbolizing perfection at its finest, enlightenment, and heavenly bliss. Efforts to discover the philosopher’s stone were known as the Magnum Opus, the “Great Work.”]

18 [Zoophytes, strictly speaking, animals that visually resembles a plant, for example, a sea anemone, but more broadly applied by early naturalists to a diverse assemblage of primarily sessile, radially symmetrical invertebrates, including ctenophores, corals, sponges, sea and brittle stars, sea urchins, etc.; an obsolete term in modern science but used by Cuvier in his Le Règne Animal of 1816, as the title of one of his four divisions (Embranchements, roughly corresponding to phyla) of the animal kingdom (called Radiata in English translations).]

19 [Medulla, the inner region of an organism, an organ, or tissue, especially when it is distinguishable from the outer region or cortex, as a kidney, an adrenal gland, etc.]

20 [Articulate animals, organisms made up of joints or consisting of segments united by joints; more specifically one of four divisions (Embranchements, roughly corresponding to phyla) of the animal kingdom, based on comparative anatomy, each with a different body plan, and detailed by Cuvier in his Le Règne Animal of 1816: zoophytes or radiata (echinoderms, cnidarians, and other forms), articulated animals (arthropods and annelids), molluscs, and vertebrates.]

21 [The encephalon is the brain of vertebrates, the area of the central nervous system that contains all higher nervous centers, enclosed within the cranium and continuous with the spinal cord.]

22 [The vertebrate skull or cranium was once assumed to be segmented along the anteroposterior axis, in a manner similar to that of vertebrae in the trunk (see the reviews of Goodrich 1930, and Jollie 1977); near the end of nineteenth century, this traditional concept was largely substantiated by elasmobranch embryology. Subsequent studies of the cyclostome cranium, however, have contributed little to substantiate this concept. For more on the evolutionary origin of the cranium, see Kuratani et al. 2016.]

23 [It is intriguing to imagine how our editor would have modified his views had he benefited from evolutionary theory —Darwin’s On the Origin of Species (1859), however, was still 20 years away.]

24 [Axilla, the space below the shoulder through which vessels and nerves enter and leave the upper arm; or the wing, as in the case of birds.]

25 [The bones of birds are hollow, a fact that helps them fly; but, contrary to popular belief, it is not because hollow bones make them lighter —it is because they need so much oxygen to fly that their lungs actually extend into their bones.]

26 [Lavoisier, see Volume 2, Lesson 10, note 78.]

27 [Reptile, a term dating to the early fourteenth century, from Old French and directly from Late Latin, a “creeping or crawling animal.” Precise scientific use began to develop in the mid-eighteenth century, but initially the word was used as well for animals now known as amphibians, including frogs, toads, salamanders, newts, and caecilians. Formal separation of Reptilia and Amphibia as distinct classes did not take place until the early nineteenth century, but popular usage lagged and “reptile” was still used in the late-eighteenth century to indicate any animal that “creeps upon many feet,” sometimes including certain invertebrates, such as scorpions, and often excluding snakes.]

28 [Ruminants are mammals that acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial action. The process, which takes place in the front part of the digestive system and therefore is called foregut fermentation, typically requires the fermented ingesta (known as cud) to be regurgitated and chewed again. The process of re-chewing the cud to further break down plant matter and stimulate digestion is called rumination. The word “ruminant” comes from the Latin ruminare, which means “to chew over again.” The roughly 200 species of living ruminants consist of both domestic and wild species; they include cattle, all domesticated and wild bovines, goats, sheep, giraffes, deer, gazelles, and antelopes.]

29 [Sternum or breastbone, typically a long flat bone located in the central part of the chest of vertebrate animals, which connects to the ribs via cartilage and forms the front of the rib cage, thus providing surface area for the attachment of muscles and helping to protect the heart, lungs, and major blood vessels from injury.]

30 [Pectoral muscles, those that connect the front of the chest with the bones of the upper arm and shoulder. The pectoralis major is a thick, fan-shaped muscle, which makes up the bulk of the chest muscle; it lies under the breast and serves to flex, extend, and rotate the humerus, the long bone of the upper arm. The pectoralis minor is a thin, triangular muscle located beneath the pectoralis major; it attaches to the ribs, and serves to stabilize the scapula, the large bone of the shoulder.]

31 [Spiracles, tiny holes in the exoskeleton of insects and some spiders that allow air to enter the trachea (see note 32, below). In the respiratory system of insects, the tracheal tubes primarily deliver oxygen directly to the tissues of the animal. The spiracles can be opened and closed in an efficient manner to reduce water loss. This is done by contracting closer muscles surrounding the spiracle. In order to open, the muscle relaxes. The closer muscle is controlled by the central nervous system but can also react to localized chemical stimuli. Several aquatic insects have similar or alternative closing methods to prevent water from entering the trachea. The timing and duration of spiracle closures can affect respiratory rates. Spiracles may also be surrounded by hairs to minimize bulk air movement around the opening, and thus minimize water loss.]

32 [Trachea, a tube or system of tubes that carries air. In insects, a few land arachnids, and myriapods, the trachea is an elaborate system of small, branching tubes that carry oxygen to individual body cells; in most land vertebrates, the trachea is the windpipe, which conveys air from the larynx to the two main bronchi, with the lungs and their air sacs as the ultimate destination. In some birds, such as the swan, there is an extra length of tracheal tube coiled under the front of the rib cage. The cartilaginous structures that ring most mammalian tracheae are reduced to small irregular nodules in amphibians.]

33 [While the trachaea of insects always remain open, the spiracles that allow air to enter the trachaea can be opened and closed to reduce water loss; see note 31, above.]

34 [Humors, the four bodily humors, based on the bodily fluids of blood, phlegm, black bile, and yellow bile, the proper balance of which was thought to be essential for good health. Humoral theory, also known as humorism or the theory of the four humors, was a model for the workings of the human body. It was systemized in Ancient Greece, although its origins may go back further still. The theory was central to the teachings of Hippocrates and Galen and it became the dominant theory in Europe for many centuries. It remained a major influence on medical practice and teaching until well into the nineteenth century.]

35 [Vegetal “blues” include plums, beets, eggplant, red grapes, and purple cabbage.]

36 [Bile duct, a thin tube in the gastrointestinal tract that allows for the flow of bile from the liver and gallbladder to the small intestine, where the bile helps to digest fats.]

37 [The cystic duct is the short tube that joins the gallbladder to the common bile duct, which allows bile to flow in both directions between the gallbladder and the common bile duct and the hepatic duct.]

38 [Cryptogam, a plant (in the broad sense of the term) that reproduces by spores, without flowers or seeds, including a wide variety of organisms such as algae, lichens, mosses and ferns, as well as non-photosynthetic organisms traditionally classified as plants, such as fungi, slime molds, and bacteria. At one time, cryptogams were formally recognized as a valid taxonomic assemblage within the plant kingdom but this is no longer the case; fungi, in particular, are regarded as a separate kingdom, more closely related to animals than plants, while blue-green algae are now regarded as a phylum of bacteria.]

39 [Monocotyledons, commonly referred to as monocots, are flowering plants (angiosperms) whose seeds typically contain only one embryonic leaf, or cotyledon. They constitute one of the major groups into which the flowering plants have traditionally been divided, including about 60,000 species. The largest family in this group by number of species are the orchids, with more than 20,000 species. About half as many species belong to the true grasses, which are economically the most important family of monocots. In agriculture the majority of the biomass produced comes from monocots. These include not only major grains (rice, wheat, maize, etc.), but also forage grasses, sugar cane, and the bamboos. Other economically important monocot crops include various palms, bananas and plantains, gingers and their relatives, turmeric and cardamom, asparagus, pineapple, water chestnut, and leeks, onion and garlic. Additionally, many houseplants and most of the horticultural bulbs, plants cultivated for their blooms, such as lilies, daffodils, irises, amaryllis, cannas, bluebells and tulips, are monocots.]

40 [Dicotyledons, also known as dicots, one of two groups into which all the flowering plants or angiosperms are placed, the other being the monocotyledons, or monocots (see note 39, above). The name refers to one of the typical characteristics of the group, namely that the seed has two embryonic leaves or cotyledons. There are around 175,000 species within this group, of which about half are woody plants; the rest include a broad array of ornamental flowers, fruits, and vegetables.]

41 [Soliped, a mammal having a single hoof on each foot, including horses, asses, and mules, etc.]

42 [The slowworm, Anguis fragilis, is a legless lizard native to Eurasia.]

43 [The Great Chain of Being (in Latin, Scala Naturae, “Ladder of Being”), a hierarchical structure of all matter and life, thought in medieval Christianity to have been decreed by God; a concept originating with Aristotle, Plato, Plotinus, Proclus, and others, and further developed during the Middle Ages, reaching full expression in early modern Neoplatonism. The chain starts with God and progresses downward to angels, demons, stars, moon, kings, princes, nobles, commoners, wild animals, domesticated animals, trees, other plants, precious stones, precious metals and other minerals. Although abandoned in early twentieth-century science, as the notion of modern organisms representing ancestors of other modern animals was abandoned in biology, the idea of a certain sequence from “lower” to “higher” lingers on, as does the idea of progress in biology.]

44 [Coccyx or tailbone, the final segment of the vertebral column in all apes, and of homologous structures in certain other mammals such as horses. In tailless primates (e.g., humans and other great apes), the coccyx is the remnant of a vestigial tail.]

45 [Carpus or wrist, a group of bones that forms the joint between the forearm and the hand; also a joint in quadrupeds that corresponds to the wrist.]

46 [Ischium, one of three bones (situated below the ilium and behind the pubis), the fusion of which forms the pelvis or hip.]

47 [Sacrum, in human anatomy, a large triangular bone at the base of the spine that forms by fusion of sacral vertebrae S1 through S5, between 18 and 30 years of age.]

48 [Calcaneum, a bone of the tarsus of the foot that constitutes the heel.]

49 [Interparietal, a dermal bone of the cranium situated between the parietal and supraoccipital.]

50 [The reference here is to the cranial nerves of vertebrates, the nerves that emerge directly from the brain (including the brainstem), in contrast to spinal nerves, which emerge from segments of the spinal cord. Cranial nerves relay information between the brain and parts of the body, primarily to and from regions of the head and neck. They are generally named according to their structure or function; for example, the olfactory nerve (I) mediates smell, the optic nerve (II) mediates vision, etc.]