132 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 58. 



We might conclude therefrom that as a whole the fauna belongs to 

 about the middle of the Pleistocene. Inasmuch as in the list are 

 found no remains of Elephas impei^ator, or of any camels, or of any 

 horses, there seems to be no special reason for holding that it is older. 

 Possibly the shaft had not been opened to the surface during the 

 early Pleistocene. 



PISCES. 

 Family CYPRINIDAE. 



ALISODON, new genus. 



Type species. — Alisodon minis, new species. 

 Type formation. — Pleistocene. 



Diagnosis. — Pharyngeal teeth in one row, probably 3-3; stalked; 

 the grinding surface expanded and deeply concave. 



The name is derived from "aXetcov a cup, and ociova a tooth. 



ALISODON MIRUS, new species. 



Plate 9, figs. 8-9. 



Type specimen. — A pharyngeal bone bearing two teeth (Cat. No. 

 9219, U.S.N.M.). 



Type locality. — Bexar County, Texas. 



Type formation. — Pleistocene. 



Diagnosis. — Same as for the genus. 



In the collection made by Mr. Schuchardt there is a single tooth- 

 bearing pharyngeal bone (Cat. No. 9219) of a cyprinid fish, on 

 which there are retained two teeth (pi. 9, figs. 8, 9.X2). Be- 

 tween these teeth there is a considerable space, which was, in life, 

 probably occupied by another tooth ; and on the bone there appears 

 a scar which may mark the place where this tooth was attached. 

 There seems to be no reason for supposing that there was a second 

 row of teeth ; hence the tooth formula is probably 3-3. From one ex- 

 tremity of the bone to the other, in a straight line, is 14 mm. The 

 teeth are of unusual form. The larger one consists of a basal pedicel 

 about 3.5 mm. wide and 1.5 mm. thick, and an expanded portion 

 about 4.5 mm. wide. The masticatory surface is deeply concave, 

 with the rim somewhat irregular. The smaller tooth has practi- 

 cally the same form. 



The writer has found no reference to similar teeth, except in Day's 

 Fishes of India (vol. 2, p. 555), where the teeth of Amblypharyn- 

 godon m.elettimis, a species of southern India, are said to have rather 

 concave summits. In that genus, however, there are three rows of 

 teeth on each pharyngeal. 



Alisodon seems to fall into the subfamily Mylopharodontinae ^ 

 and next to the genus Stypodon. This genus is described as having 



> Tordan atirt Evermaiin, Bull. 47, U. S. Nat. Mus., p. 202. 



