JO BLIND VERTEBRATES AND THEIR EYES. 



burrow in the ground. Anicll<i, a small, legless, burrowing lizard of California, 

 probably indicates their origin. This lizard has well-developed eyes. It burrows 

 in sand and gravel. I have- frequently seen it cautiously thrust its head out of the 

 ground for an instant as if to take a survey of the field. It evidently still uses its 



eyes. 



Amphisbaenians, 1 which are widely distributed over the warm parts of the globe, 

 burrow in the ground or live in ant hills, and are partially or totally blind. The 

 blind snakes, members of the Typhlopidae, have similar habits. 2 



Many salamanders live in damp earth under logs or rocks. It is but natural, 

 therefore, that they should be found in or about the entrances to caves, where 

 sheltering rocks are not infrequent. Others are true cave animals. Two of the 

 salamanders in North America that habitually live in caves have apparently quite 

 normal eyes. They are Spelcrpes miiciilicauda found from Indiana and Kentucky 

 to Missouri, and Sprlcrpes slcjuc^cri from southwestern Missouri. Two others 

 living in caves have quite degenerate eyes, Typhlotriton spelaus from caves in 

 southwestern Missouri, and Typhlomolge mthbuni from the caves of Texas. Pro- 

 teus, the nearest relative of the latter, lives in the caves of Carniola. There are no 

 blind epigean salamanders. Of Anura there are no permanent residents in caves, 

 nor are there any blind forms. A jumping animal would be sure to meet with dis- 

 aster in a cave if it practiced its usual mode of progression. 



The classes of vertebrates furnishing the largest number of blind forms are 

 the fish and fish-like vertebrates. Excluding the Branchiostoma, the Cyclostomes 

 have for the most part degenerated eyes. Polistotrema stouti is quite blind. 



Benthabatis moresbyi Alcock is a blind Torpedinid Selachian from Travancore, 

 from a depth of 430 fathoms. 



Of the lowest teleosts the Siluridse are represented by Gronias nigrilabris Cope, 

 which occurs in a cave near Philadelphia. 3 The eyes of many other cat-fishes are 

 not highly orga nixed and but little used in detecting food. 4 Other cat-fishes are 

 occasionally met in caves, but no others are permanent residents. 



The cave fishes of North America, par excellence, are the Amblyopsidse. All 

 the members of this family, 8 in number, have degenerate eyes; 5 have mere ves- 

 tiges; u permanently live in caves; i is known only from a spring and another 

 from open streams. These will be considered in detail later. 



In Cuba j hshes belonging to a marine family, the Brotulid;c, have become 

 adapted to a cave life in fresh water. Both are blind. Many of their marine 

 relatives are also blind. 



Along the coast from San Pedro, California, to Encenada, Lower California, 

 but more particularly at the foot of Point Loma, a blind goby lives under rocks 

 eml in sand between high and low tide. 



and many live in ant nests. They bore narrow galleries 



t>ai 1 wards as well as forwards. On the ground they progress 



i ions, mil by lalnal movrnu-nis, as in other limbless reptiles; the tail 



e Tin- food of these lizards consists of small insects and 



'd in this account; Man- American, of which only a 



li of the Tropic of Cancer, and i i Impkisbana) in the West Indies." Boul- 



tn g^ r - ' ' iSSq. 



' in the Vmericas, as far north as Cuba: Tvplilops lion- 

 ind 7>/./;//<.v l,-i,,,is, Guatemala and Mrxiro. 

 illy IHVII drsnilird from I!ia-il. 



it bj tni in ol theii .-ves or olfartorv organs, but 

 i 'i barbels. 



