214 ZOOLOGY. 



HvpSiEiD^.. This highly remarkable family is established on a single 

 species, the Amhlyopsis spelaens, or blind fish of the Mammoth Cave of Ken- 

 tucky. It is characterized by a form much like that of a Hydrargira, to 

 which it would at first be referred. The head, however, is much depressed, 

 and the eyes are entirely wanting, none being evident even on dissection. 

 The body is covered with scales, and the jaws provided with fine teeth. 

 The intestinal canal is shorter than the body. Coecal appendages two, 

 pyriform, and opening by distinct orifices in each side of the intestine. Air- 

 bladder heart-shaped, deeply cleft anteriorly. The anus is situated anterior 

 to the base of the pectorals. The fins are provided with filamentous tips. 



This very curious fish combines the characters of the Esocida;, SalmonidcB, 

 and Cyprinodontidce, although its affinities are most with the latter. Like 

 these, too, it is ovo-viviparous, the young being from ten to twenty in 

 number. The color is a dull white. The animal is caught in a stream of 

 water flowing across the Mammoth Cave, in which it is readily seen by the 

 contrast of its white sides with the darker body of the water. A species 

 of Astacus, A. pellucidus, likewise white and destitute of eyes, inhabits the 

 same water in great quantity. 



CvpRiNODONTiDyE. Thc spccics of this family, which experiences its 

 (greatest development in America, are generally of small size. In fact a 

 certain species found in South Carolina is not much over half an inch in 

 len<nh, even when comparatively large, and the others are not of much 

 *n*eater magnitude. IMost are inhabitants of brackish water, although all 

 the fresh waters of North America have their representatives. Body 

 variously shaped, generally elongated and sub-depressed, especially anteriorly. 

 The fins are all rounded, and the dorsal is situated far back, above the 

 anal. The jaws are provided with small teeth which are sometimes den- 

 ticulated. Hooked teeth on the pharyngeals. Air-bladder single. The 

 principal genera are : Fundulus, Lebias, MoUinesia, Hydrargira, and 

 Cyprinodon. Some of these are remarkably tenacious of life. Species of 

 Hydrargira have resisted the influence of the air-pump vacuum, under 

 circumstances where the same deprivation of air would have killed almost 

 any other fish. This genus can live for months buried in soft mud, after 

 their native pond dries up, coming out again on the accession of fresh water 

 Cyprinid^. We come now to the consideration of the family of 

 the Cyprinidce, which embraces by far the greater number of the exclusive 

 residents of fresh waters. Every variety of size and shape occurs ; the 

 flesh, however, of but few, is worth much as an article of food. They are 

 distributed over all the temperate and cooler waters of the globe, their 

 occurrence in tropical waters being very limited. The family is character- 

 ized by the absence of teeth in the mouth, and the development of teeth 

 of various kinds and shapes upon the posterior branchial arch, or pharyngeal 

 bone. The shape and number of these teeth furnish excellent generic 

 characters. The former are exceedingly varied, each region having some 

 peculiar to it : as Schizothorax for Syria, Catastomus and Exoglossum for 

 North America, &c. A prominent European form is Chondrostoma nasus 

 {pi. 84, fig. 4). Alburmis lucidus, or the bleak, represented in pi. 84, fig. 

 418 



