MUSEUM OF COMPARATIVE ZOOLOGY. 89 



Some of the following species have a special interest on account of their 

 locality. The majority are from small streams or springs flowing into the 

 Lago del Muerte or the Lago de Parras, in the southwestern part of the State 

 of Coahuila, Mexico. These lakes or lagoons are said to be completely isolated. 

 They are marked so on the latest maps of this portion of the country. The list 

 is compiled from a collection made for the Museum by Dr. Edward Palmer. 



Noturus flavus Rap. 

 San Antonio, Texas. 



Ichthyobus tumidus Girard. 



D. 3 + 26; A. 3 + 8 ; V. 11 ; P. 16 ; L. lat. 37 ; L. trans. 7 + 1 + 5. 

 San Pedro, on the Nazas River, flowing into the Lago del Muerte from the 

 west. 



Catostomus nebuliferus sp. nov, 



D. 3 + 9; A. 2+8; V. l + 8(-9); P. 15 ; L. lat. 90 ; L. trans. 14+1 + 14. 



Length of head or height of body one fifth of the total, exclusive of the 

 caudal. Body stout, little compressed. Head moderate, nearly as broad as 

 high, length in front of the eye almost twice the diameter of the orbit. Eye 

 small. Mouth small ; lips with a considerable free margin. Anterior spine 

 of the dorsal midway between the muzzle and the caudal ; a vertical from 

 the middle of the base of the fin reaches the insertion of the ventrals ; the 

 latter extend to a vertical from the posterior extremity of the free portion. 

 Caudal deeply notched. Anterior rays of dorsal and ventral longer. 



Reddish brown to brown, clouded and blotched with darker. Darker 

 along the lateral line. Belly light colored, uniform. Lower half of the pre- 

 opercle silvery white. The line of demarcation between the dark color of 

 the upper portion of the head and the light of the face and throat is very 

 distinct. Allied to C. guzmanensis Girard ; differing in the radial formulae 

 and, somewhat, in coloration. It differs from C. griseus Girard in radial for- 

 mula), squamation, and colors. 



Nazas River. 



Hybognathus (Dionda) punctifer sp. nov. 



D. 2 + 8 ; A. 2 + 8 ; V. 8 ; P. 16 ; L. lat. 40 ; L. trans. 5 + 1 + 3. 



Teeth 4-4, compressed, clawed. 



Length of head or height of body equal to one fourth of the total, without 

 caudal. Body but slightly compressed, outline from forehead to dorsal curving 

 regularly. Head moderately V)road ; snout rounded, little, if any, longer from 

 the eye than the diameter of the orbit. Eye medium. Mouth small ; maxil- 



