476 ZOOLOGY. 



The so-called liminous organs present no essential difference of 

 structure from the preceding. 



Organs exhibiting the characteristics of these parts, it is urged, can- 

 not be sensory, much less endowed with the function of sight. The ob- 

 jections to their consideration as eyes are given in detail, and of the so- 

 called lens it is said that "it does not lie in the center, but at the edge of 

 the mass which does duty as the vitreous body," and its histology is also 

 antagonistic to an analogy with the lens, and, " greatest difficulty of all, 

 the ' pupil,' the '■ lens,' and the ' vitreous body' are not turned upwards to 

 the light, but so long as the fish is swimming they look downwards into 

 the deep ; and in the case of ChauUodus are developed also on the mem- 

 brane that lines the cavity of the mouth." 



What, then, are these organs ? According to Leydig, the problem- 

 atic bodies " bear the closest resemblance to the electric or ' pseudo- 

 electric' organs of other fishes, and he brings many points to strengthen 

 his position." Different as the electric organs are in form as well as 

 position, in all they are richly supplied with nerves; they are surrounded 

 by a layer of connective tissue, which gives rise to a number of ' ' alveolar " 

 chambers filled with a gelatinous substance. Now, on comi)arison with 

 these of the eye-like spots of the fishes, it is found that in this one as 

 in the other there is '* a contained mass of gelatinous tissue," and " the 

 same net- work of connective tissue," as well as "nerve fibres of very 

 much the same character." Still other points of resemblance are ad- 

 duced, but " whether they really have the power of developing elec- 

 tricity is a problem that cannot yet be solved." As to their phosphores- 

 cence, it is contended that " no definite phosphorescent organ has ever 

 yet been examined which presented any other contents than fatty or 

 oily matter." Conceding all the j^ostulates claimed by Professor Leydig, 

 however, in view of the surroundings of the animals developing the 

 organs treated of, we can scarcely avoid the belief that they have some 

 relation to illumination. In the words of Professor Bell, " it still re- 

 mains possible that these creatures add to the feeble light of great ocean 

 depths by reflecting the light that fall on these eye-like organs," although 

 their function as such may be a secondary development. 



The Facijic Coast salmon. 



The species of salmon -like salmonidae found upon the Pacific coast 

 of jSTorth America and its entering rivers have been unduly multi- 

 plied, and much confusion has existed as to the limits of the spe- 

 cies. With more ample material than was enjoyed by any of their 

 predecessors, and, above all, the privilege of seeing the fishes in their 

 haunts, Messrs. Jordan and Gilbert have revised all the known forms 

 and have reduced them to five species. All belong to the genus Onco- 

 rhynchus, which differ from the Salmo in the greater number of rays in the 

 anal fin, and accessory but slight modifications of the snout. The males 

 of all the species when running into fresh water assume an attenuated 



