[33] See p. 167, Figs. 79, 81.
[34] See p. 136, Fig. 58.
[35] See p. 167, Fig. 78.
[36] The cartilaginous jaws of Sharks shrink at least a third in drying, and, therefore, cannot be kept at full stretch without tearing.
[37] This exception is a Ray obtained during the “Challenger” expedition, and said to have been dredged in 565 fathoms.
[38] See pp. 73 and 74, Figs. 35 and 36.
[39] For other illustrations see p. 73, Fig. 35 (palatal view of head); p. 74, Fig. 36 (pectoral skeleton); p. 141, Fig. 60 (gills); p. 148, Fig. 65 (lung); p. 151, Fig. 67 (heart); p. 134, Fig. 57 (intestine); p. 165, Fig. 77 (ovary).
[40] See p. 97, Fig. 41; and p. 152, Fig. 68.
[41] The Acanthopterygians do not form a perfectly natural group, some heterogeneous elements being mixed up with it. Neither are the characters, by which it is circumscribed, absolutely distinctive. In some forms (certain Blennioids) the structure of the fins is almost the same as in Anacanths; there are some Acanthopterygians, as Gerres, Pogonias, which possess coalesced pharyngeals; and, finally, the presence or absence of a pneumatic duct loses much of its value as a taxonomic character when we consider that probably in all fishes a communication between pharynx and air-bladder exists at an early stage of development.
[42] In this instance, one may entertain reasonable doubts as to the usefulness of the Pilot to the Shark.