Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . ecologicalanimal00hess Year: 1937 2() MARINE ANIMALS hibited by the so-called telescopic eyes (Fig. 70). These are found only in the smaller fishes, of which the largest, Gigantura chuni (Fig. 71), measures cm. Such telescopic eyes have developed independ- ently in five different orders and eight suborders of fishes. A deep-sea cephalopod also has eyes of this The similarity of the frontal eyes of pelagic deep-sea crustaceans is only apparent, although there is also
Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . ecologicalanimal00hess Year: 1937 2() MARINE ANIMALS hibited by the so-called telescopic eyes (Fig. 70). These are found only in the smaller fishes, of which the largest, Gigantura chuni (Fig. 71), measures cm. Such telescopic eyes have developed independ- ently in five different orders and eight suborders of fishes. A deep-sea cephalopod also has eyes of this The similarity of the frontal eyes of pelagic deep-sea crustaceans is only apparent, although there is also a relative enlargement of the light-gathering surface. As a further adaptation to the small amount of abyssal light, the retina of the deep-sea fishes of all groups has only the light-sensitive rods; the cones are Nr- u—i \ - Fig. 70.—Telescopic eye of the deep-sea fish Argyropelecus in transverse sec- tion, with the dotted outline, U, of a normal eye for comparison. C, cornea; L, lens; R, retina; Nr., pigmentary layer. After Brauer. In correlation with reduced eyes, and even with well-developed eyes, in connection with this limited capacity for orientation in the dim light, numerous deep-sea crustaceans and fishes possess antennae of unusual length in comparison with those of their relatives in the lighted zone. Sergestes magnijicus from 800 to 1200 m. has antennae three times the length of the body; Arachnomysis, with well-developed eyes, has antennae four times the length of the body; in the isopod, Mun- nopsis longicornis (600-800 m. depth), the antennae are more than eight times the body length, and in the shrimp Aristaeus they measure 10 to 12 times the length of the body. In numerous fishes, such as Bathypterois (Fig. 72), single rays of the various fins are developed as feelers and are longer than the body. A high development of the lateral line system is also notable in many deep-sea fishes. Similar develop-
Size: 1155px × 1732px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
