214 ZOOLOGY. 
Hyrszw#. This highly remarkable family is established on a single — 
species, the Amblyopsts spelaens, or blind fish of the Mammoth Cave vf 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. Cccal 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 Hsocide, Salmonide, 
and Cyprinodontide, although its affinities are most with the latter. Like © 
these, toe, it 1s 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. 
Cyprinopontw#. The species 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 
length, even when comparatively large, and the others are not of much 
greater magnitude. Most 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, Mollinesia, 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 
Cyprinioz. We come now to the consideration of the family of 
the Cyprinidae, which embraces by far the greater number of the exclusive 
residents of fresh waters. Eivery 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 
(pl. 84, fig. 4). Alburnus lucidus, or the bleak, represented in pl. 84, Jig. 
418 
