[21] CATALOGUE OF THE FISHES OF NORTH AMERICA. 



75.— DIONDA^ Girard. (77 pt.) 



206. Diouda melauops Girard. Vsw. (189) 



207. Dionda pmictifera Garuian. Vsw. (1886.) 



208. Dionda fluviatilis Girard. Vsw. (188) 



209. Dionda amara Girard. Vsw. (183) 



210. Dionda episcopal Girard. Vsw. (184,187) 



211. Dionda serena' Girard. Vsw. (18.5) 



212. Dionda nubila' Forbes. Vw. (200) 



213. Dionda (?) haematura 5 Cope. Vn. (204) 



76.— HYBOGNATHUS Agassiz. (78) 



214. Hybognathus meeki*' Jordan & Gilbert. Vw. 



215. Hybognathus argyritis' Girard. Vnw. 



216. Hybognathus nuchalis^ Agassiz. V. (182) 

 216 b. Hybognaihus nuchalis pladta^ GiTiirCL. Vw. (186) 



' The genu,s DiotuJa may perhaps bo recognized as distinct from Hyiognathus. Its 

 teeth are shorter than those of Hyiognathus, and more or less distinctly hooked. The 

 species are small in .size and mostly dusky in coloration, being especially character- 

 istic of the Rio Grande region. 



- DiondOf episcopa Girard, Dionda iexensis Girard, Dionda argentosa Girard (types of 

 these three examined bj' us) = Hyiognathus flavipinnis Cope. Fairly described in the 

 Synopsis undertheuameof i/(/6o(7na//iJ(8_^aripiwnt8. The number of scales in the lateral 

 line is about 37 in the types of episcopa and argentosa, 37 to 39 in texensis, and 41 in 

 Havipinnis. The anterior suborbitals are of moderate width in Z>. episcopa, about as 

 in Hybognathus nuchalis. 



■^Dionda screna Girard =: Dionda chrysitis Grd. = Hyiognathus nigrotceniatus Cope. 

 Fairly described in the Synopsis under the latter name. The eye is smaller in serena 

 than in episcopa, and the scales are larger (34 in the type of D. serena). 



■•Described in the Synopsis, page 167, as Cliola nubila. The species belongs, how- 

 ever, to Dionda, as has been already noticed by Professor Forbes. D. nubila is very 

 close to D. episcopa, but from the specimens compared it appears to differ from the 

 latter in the more pointed snout and in the larger mouth, the cleft of the mouth form- 

 ing about one-fourth the length of the head, instead of one-tifth, as in D. episcopa. 



■^A doubtful species, unknown to me. The description points rather to this genus 

 or Cliola, than to 2sottopis. 



'■ Hybognathus meeki Jordan & Gilbert, Proc. U. S. Nat. Mus., 1885. Ozark region of 

 Missouri and Arkansas; abundant. 



"The types of Hybognathus argyritis from the Upper Missouri belong to a species 

 distinct from H. nuchalis, and are distinct from the sjiecies heretofore called H. argyritis 

 by different authors. The suborbitals in H. argyritis are broad, as in H. nuchalis and 

 H. placita, the anterior being about twice as long as deep ; the mouth is larger than 

 in the other species, its cleft extending nearly to the eye ; the jaws subequal, the 

 lower being acntish at tip. The species is known only from the Upyjer Missouri and 

 the Red River of the North. Hybognathus evansi Girard is possibly the same, but the 

 types are lost and the description is too brief for identification. It is more likely H. 

 nuchalis. 



*This species ranges from New Jersey to South Carolina, Texas, and Dakota. H. 

 osmerinus and H. regius being indistinguishable from it. It has the suborbitals broad, 

 the mouth small, the lower jaw short, blunt, and subhorizontal, and the eye large, 

 about 4 in head. 



'^ Hybognathus placita, now known from the Arkansas and Missouri Rivers, is closely 

 related to H. nuchalis, but has the eye smaller, about 5 in head, the snout depressed 

 and rather blnnt ; mouth very small. 



