NATURAL SCIENCESOF PHILADELPHIA. 63 



Girardinus formosus, is quite as common in ponds and ditches, as the species 

 treated of in the preceding paragraph, especially about the rice fields and 

 inlets of rivers and brooks. Their great abundance has brought them to the 

 notice of every planter at the South, where these fishes are met with. 



XIII. A "blind fish, taken from a well near Bowling Green, Ky.," was 

 recently sent to the Smithsonian Institution by J. E. Younglove, Esq. 



In its general appearance and chief structural traits it resembles that which 

 occurs in Mammoth cave, with this curious difference, that the ventral fins are 

 wanting : we will call it Typhlichthys subterraneus. 



Some years ago a fish ( Chologaster cornutus) was found in the ditches of the 

 rice fields of South Carolina, in all appearances akin to Amb ly op sis spelceus, hav- 

 ing the same advanced position of the vent, the body being covered with simi- 

 lar scales, but the ventral fins are wanting and the eyes fully developed.* 



We have not yet been informed of the nature of the dentition of Chologaster 

 cornutus. That of Typhlichthys subterraneus is similar to the dentition of Ambly- 

 opsis spelceus, and consisting of narrow patches of acute and very minute teeth 

 upon the premasillar bones, the palatines and the lower jaw. 



These three genera have for common traits of structure : a body covered by 

 cycloid scales, a dorsal and an anal fin opposed to one another, a rounded off, 

 or sublanceolated caudal fin, the position of the vent anterior to the base of 

 the pectoral fins. The shape of the mouth and the dentition are in all proba- 

 bilities alike. The generical characters consist : in Amblyopsis, the want of 

 eyes and the presence of ventral fins ; in Typhlichthys, the want of eyes and 

 ventral fins, both, and in Chologaster, the presence' of eyes and the want of ven- 

 tral fins. 



The propriety of establishing three genera upon characters apparently tran- 

 sitory may be questioned by those who believe in the doctrine of transforma- 

 tions. Were Chologaster provided with ventral fins, and to differ from Amblyop- 

 sis by the presence of well developed eyes alone, the plausibility of a trans- 

 formation of that organ according to circumstances might seduce many. But 

 then again comes Typhlichthys, which holds an intermediate position, perfectly 

 eyeless and deprived also of ventral fins. 



The largest specimens which we have seen of Typhlichthys subterraneus 

 measure a little over one and a half inch. The head which enters about three 

 times and a half in that length, is depressed, and broader than deep. The 

 mouth is proportionally large and transverse, the lower jaw being somewhat 

 longer than the upper. Minute and acerated teeth may be observed upon the 

 lower jaw, the premaxillar bones, and on the palatines also, disposed upon 

 narrow patches. The eyes exhibit no visible traces of their presence, the orbit 

 being filled up by a muscular tissue. The branchial apertures are separated 

 under the throat by a narrow isthmus, the branchiostegal rays being six in 

 number on either side. The body anterior to the dorsal and anal fins is sub- 

 cylindrical, whilst it is compressed and tapering posteriorly ; its entire profile 

 being subfusiform. The vent is situated in advance of the pectoral fins and 

 close to the branchial isthmus. The height of the dorsal fin is greater than 

 its base ; its anterior margin is nearer the extremity of the caudal fin than the 

 apex of the snout. The caudal is rounded oft' posteriorly or sublanceolated, 

 the central rays being the longest. The anal fin is inserted nea.rly opposite the 

 dorsal, or else somewhat more posteriorly ; it is likewise deeper than long. 

 The centrals, as alluded to above, are entirely wanting. The pectorals are 

 slender and elongated ; their middle rays being the most developed. The 

 number of the rays in the various fins is as follows : D 7 ; A 8 ; C 4, 1, 6, 6, 

 1, 5 ; V ; P 11 ; a formula very similar to that of Amblyopsis spelceus. The 

 scales are very small, subimbricated, firmly adhering to the skin without 

 being imbedded in it as in the species just alluded to. They are rather 



* Amer. Jour, of Sc. and Arts, Second Series, xvi, 1853, 135. 

 1859.] 



