CHIHtBRA AND ITS CHARACTERISTICS. l * 



conspicuous anterior rim to the dorsal fin, whose remaining margin, in reality of a 

 dark umber, now appears jet-black. In side view the body of the fish exhibits white 

 spots, but they are not noticed in many positions. From above, however (fig. 2), they 

 are conspicuous, and the general ground tone of the fish appears much darker, a 

 change in coloration which is probably of value for protection. 



In the matter of color Chimcera colliei is not far from the mean of recent 

 Chimaeroids ; for some of these have but little pigment, while others are dusky 

 and even black. This range in color might be expressed in somewhat the following 

 way : With least pigment are the Callorhynchids, with clear silvery sides, obscured 

 only by several large lateral blotches, and Chimara pliantasma, with silvery sides 

 marked with longitudinal dark stripes. With increase of pigment come the series 

 C. monstrosa, C. affinis * C. colliei, C. mitsukurii, C. piirpurascens, and C. ogilbyi, 

 the last almost entirely black. The distinctly abyssal types, unshaded, uniformly 

 plumbeous, with pigmented lateral line, are Rhinochimaera, Harriotta, and C. plumbed. 



SIZE. 



The general relations of size in Chimaeroids will be referred to on a later page. 

 The recent forms present a range of length from about 60 to 200 cm. C. mitsu- 

 kurii, even including its long opisthure, is the smallest species, and the gradation 

 in size extends somewhat as follows through the series : C. colliei, C. affinis, C. 

 monstrosa, C. ogilbyi, and C. phantasma; and in the neighborhood of a meter in length 

 are all other forms except C. purpurascens. Following the general rule among 

 other fishes, males are smaller than females; in length less by about one-twelfth, and 

 in weight by about one-seventh. In this connection a few comments may be added 

 regarding the general shape of the fish. In Callorhynchids and in C. phantasma 

 the modeling of the head, trunk, and tail is compact and suggests that of Cestra- 

 ciont sharks. In general, males are more slender than females. This relation is 

 shown in fig. i, taken from a photograph of the freshly caught fish. 



OCCURRENCE, HABITAT. 



Chimaeroids are widely distributed (cf. species list, pp. 6, 7). Callorhynchus, 

 however, is limited to the south seas, and Chimera largely to the north. The 

 distribution of Chimaera is clearly the more general, for C. vaillanti occurs at Cape of 

 Good Hope and C. ogilbyi in Australia. It is the general belief that all Chimaeroids 

 are obtained from deep water, since the majority of the species occur at a greater 

 depth than the loo-fathom line, while some indeed are abyssal. It is stated, for 

 example, that C. monstrosa occurs in water as deep as 1,000 fathoms, C. affinis^ in 

 depths from 200 to 1,300, Callorhynchus up to 600, Harriotta from 700 to 1,000, and 

 Rhinochimaera at about 700. On the other hand, it must be admitted that C. 

 colliei occurs in relatively shallow water. Dr. Bean records (Oceanic Ichthyology, 

 p. 32) that "it swims at the surface," and states further that "there is no evidence 



*It is probable that the C. affinis recorded from great depths represents a new species. 

 fC. affinis is the most abyssal of elasmobranchs. 



