MYXOSTOMA ANISURA. 127 



l&fQPtychostomm Ireviceps CopE K Proc. Am. Philos. Soc. Phila. 478. 



Teretulus breviceps JORDAN & COPELAND, Check List, 157, 1876. (Name only.) 

 Moxostoma breviceps JORDAN & GILBERT, in Klippart's Kept. 53, 1876. (Name 



only.) 

 Myxosloma treviceps JORDAN, Bull. U. S. Nat. Mus. 9, 50, 1877. (Name only.) 



HABITAT. Ohio Valley and Great Lakes. 



This species, first described by Rafioesque in 1820, has been entirely 

 lost sight of by succeeding writers, and I, doubting the existence in the 

 Ohio River of a species characterized by the marked inequality of the 

 caudal lobes, have hitherto followed Dr. Kirtland in using the name 

 anisura for the fish recently named collapsus by Professor Cope. Some 

 specimens lately examined by me from the Ohio River have shown the 

 existence of a fish corresponding very closely to Rafinesque's account, 

 and which really has the inequality of the caudal fin, on which he lays 

 such emphasis, arid which suggested the name anisurus (unequal-tail). 

 This fish appears to be the same as that to which Professor Cope has 

 given the name of breviceps. Professor Cope had, however, but a single 

 specimen, in poor condition, and did not notice the falcatiou of the 

 caudal, or, more likely, that fin was not preserved intact. I have, some 

 time since, examined Professor Cope's type, preserved in the Museum 

 of the Academy of Natural Sciences, at Philadelphia, and believe it to 

 be identical with M. anisura Raf. The form of the head and body and 

 of the mouth are similar in the two, and the dorsal in both is simi- 

 larly falcate. 



This species resembles aureolum in every respect, except that the 

 dorsal fin is shorter, and elevated or falcate in front, the free border 

 being deeply incised, and that the caudal fin is similarly elongated, the 

 upper lobe being much the longer and greatly attenuated. 



The following are the measurements of three specimens: 10,788. from 

 Sandusky, and 12,267 and 12,294 from Cincinnati. The fractions indi- 

 cate percentage of the length to the base of the caudal : 



