70 BLIND VERTEBRATES AND THEIR EYES. 



THE AMBLYOPSID^. 



The Amblyopsidss are a small family of fishes, first brought to the notice of 

 naturalists by W. T. Craige, who presented a specimen to the Philadelphia Academy 

 in 1842. De Kay, "Natural History of New York" (Reptiles and Fishes, p. 187, 

 1842), gives a brief description of Amblyopsis spelceus. It was followed at once by 

 articles by Wyman (1843 and later, 1850, 1854 a and b) and other articles by Thomp- 

 son (1844) and by Telkampf (1844). Renewed interest in the Amblyopsidas was 

 aroused by Agassiz's discovery of an epigean relative, Chologaster cornutiis, in the 

 ditches of rice fields in South Carolina. 



Typhlichthys subterraneus was described by Girard in 1859 from a well near 

 Bowling Green, Kentucky ; Chologaster agassizii, by Putnam from a well at Leba- 

 non, Tennessee, in 1872; Chologaster papilliferus, by Forbes in 1882. In 1898 the 

 present author described Typhlichthys rosea, and a short time afterwards he 

 demonstrated that this species is generically distinct from Typhlichthys, naming 

 it Troglichthys. More recently (1905) he described Typhlichthys osborni and 

 Typhlichthys wyandolte. 



RELATIONSHIPS OF THE AM BLYOPS1D/E. 



The Amblyopsidas are members of the order Haplomi, first characterized by 

 Cope. 1 They have recently been defined by Boulenger, as follows : 



Air-bladder, if present, communicating with the digestive tract by a duct. Opercle well devel- 

 oped. Pectoral arch suspended from the skull; no mesochorochoid. Fins usually without, rarely 

 with a few spines; ventrals abdominal, if present. Anterior vertebrae distinct, without Weberian 

 ossicles. 



The order consists of a number of families of which the Galaxiidae and Aplochi- 

 tonidae are found in the fresh waters and occasionally in the oceans of the south 

 temperate zone ; the Scopelidae are found pelagic and abysmal in the ocean, the 

 Kneriidas in Africa, the Dalliidas in Alaska and Siberia, the Pceciliidse in fresh 

 water and along the shores of the tropical and temperate zones, and the Esocidas in 

 fresh waters of the north temperate zone. 



The Amblyopsidas are distinguished from the other families by the doubling 

 forward of the alimentary tract, the opening of the oviduct and anus being placed 

 close behind the throat, in front of the pectorals. 



The genera of the Amblyopsidas may be distinguished by the following char- 

 acters : 



a. Ventral fins present ; pyloric coeca 2 or 3 Amblyopsis 



aa. Ventral fins absent 



b. Eye a vestige ; pyloric cceca 2 



c. Sclera with cartilages ............ Troglichthys 



cc. Sclera without cartilages ........... Typhlichthys 



bb. Eye well developed; body pigmented; pyloric coeca 4 ...... Chologaster 



1 Proc. Amer. Assoc. Adv. Science, Indianapolis, 1872, 328 and a^. 



