1883.] NATURAL SCIENCES OF PHILADELPHIA. 151 



pharyngeal bones and teeth are preserved. I cannot distinguish 

 the specimens from corresponding parts of the common sucker of 

 Lake Klamath, named by Ayres as above. They, however, present 

 considerable variations among themselves. These may be stated 

 as follows : 



I. Ethmoid and front convex transversely. 

 a. Parietal fontanelle small. Two specimens. 

 aa. Parietal fontanelle large. Three specimens ; two of them 

 lent me by Prof. Thos. Condon, of Eugene, Or. 

 II. Ethmoid and front a little convex ; fontanelle large ; in both 

 points resembling the typical specimens from Lake 

 Klamath. One specimen. 

 III. Ethmoid and front plane, the latter a little concave in 

 profile. Fontanelle large. One specimen. 

 There are numerous other skulls in my collection, but they are 

 not yet sufficiently cleared of matrix to display their characters. 

 Catostomas batraohops sp. nov. 



This sucker is characterized by the short, wide and depressed 

 form of the cranium. The ethmoid bone is considerably more 

 than twice as wide as long (minus the spine), while in G. labiatus 

 it is only half as long as wide. The interorbital width is equal to 

 the length of the skull, minus the ethmoid bone and epiotic spine ; 

 in G. labiatus this width is a good deal less than the dimension 

 mentioned. The ethmoid and frontal bones are less convex than 

 is the case in the more common fossil variety of C. labiatus. 

 Although the bridge separating the temporal and pterotic fossae 

 is wide in G. labiatus, it is wider in the G. batrachops, and has a 

 concave superior surface, which is not separated by ridge or 

 angle from that of the superior plate of the parietal bone. There 

 is ncr frontal keel, and the fontanelle is well developed. 



Measurements. m. 



Length from epiotic spine to ethmoid spine, inclus., '084 



Length of ethmoid, minus spine, . 

 Length of frontal bone (median), . 

 Length of parietal bone (median), 

 Interorbital width. 

 Width at pterotics, about 

 Width between apices of epiotics. 

 Width of ethmoid. 



•018 

 •032 

 •015 

 •056 

 •062 

 •032 

 •042 



