Literary Notices. Ixix 



active individuals. The development of such an instinct and its per- 

 petuation by natural selection in cases of insufficiency of food is not 

 inexplicable. 



It is remarkable that such a taste, when once acquired, seems to 

 overcome the normal instinct entirely, and the morbid appetite craves 

 animal diet, even when the natural food is abundant. We are pre- 

 pared to hear of rogue caterpillars, as well as rogue elephants or 

 tigers. 



The Sense Organs of the San Diego Blind Fish.' 



The interesting little fish described lives beneath stones or buried 

 in the sand. As a result of its subterranean habits the eyes and whole 

 frontal region of the skull have been profoundly changed and the skin 

 has become highly sensitized. The paper contains much suggestive 

 material and a full resume of the literature. We have space here for 

 simply a reproduction of the author's summary : 



" I. In the smallest examples studied the eyes, though very 

 small, are distinctly visible even in preserved specimens, — so distinctly 

 that the lens is plainly seen. In the largest examples, on the other 

 hand, they are so deeply buried in the tissue as to appear even in the 

 living animals as mere black specks, while in preserved ones they are 

 in many cases wholly invisible. 



2. Neither in small nor in large specimens does the epidermis 

 over the eye differ in thickness or structure from that of adjacent 

 regions. In the large individuals the much greater thickness of the 

 tissue here is brought about by an increase in the sub-epidermal con- 

 nective tissue, the growth of which can be seen taking place in the 

 embryonal connective-tissue cells that are found here. 



3. As in the case with rudimentary organs generally, the eye is 

 subject to great individual variation in size, form, and degree of dif- 

 ferentiation. 



4. The only parts of the normal teleostean eye no traces of which 

 have been found are the argentea, the lamina suprachoroidea, the 

 processus falciformis, the cones of the retina, the vitreous body proper, 

 the lens capsule, and in one specimen the lens itself. 



5. In the parts present the rudimentary condition of the organ 

 is seen in the very slight development of the choroid, no cellular ele- 

 ments being present in this excepting in the chorio-capillaris, and here 



^ RiTTER, W. E. On the Eyes, the Integumentary sense Papillse, and the 

 Integument of the San Diego Blind Fish {Typhlogobiiis calif orniensis.) Bui. 

 Mus. Comp. Zool,, XXIV, 3, Apr., 1893. 



