SILURID^. 



71 



following synopsis. A Chinese species, Pimelodus cantonensis, referred 



by Dr. Giinther to Amiurus, is excluded, as its real position is perhaps 



uncertain. The species are most abundant in the Mississippi Valley 



and Great Lake Eegion. Some of them occur in all our waters east of 



the Eocky Mountains, but as yet none are known from the Pacific 



Slope. 



ANALYSIS OF THE GENEEA OF ICHTH^LURI. 



*. Adipose tin with its posterior margin free, not connected with the caudal fin : 

 +. Intermaxillary band of teeth convex in front, abruptly truncate behind, without 

 lateral backward processes; branchiostegals 8 or 9 (rarely 10 or 11); ventral fins 

 normally with 8 rays ; 

 t. Supraoccipital bone prolonged backward, its apex emarginate, receiving the 

 pointed anterior end of the second interspinal, thus forming a continuous bony 

 bridge from the snout to the base of the dorsal ; branchiostegals 8 or 9 ; head 

 elongate; mouth small, terminal, the upper jaw the longer; anal fin elongate, 

 of 24 to 34 rays ; caudal fin furcate ; body elongate, more or less slender, sil- 

 very, covered with thin skin Ichthjsluiius. 



tt. Supraoccipital bone free behind, not connected with the interspinal : branchi- 

 ostegals normally 9 (varying from 8 to 11) ; head broad ; mouth broad, terminal ; 

 anal fin moderate or rather long, with 15 to 27 rays ; caudal fin usually truncate, 

 but often more or less deeply emarginate or even forked ; body usually more or 



less shortened, covered with a rather thick skin Amiuuus. 



tt. Intermaxillary band of teeth convex in front, with a lateral backward extension 

 on each side; branchiostegals normally 12; supraoccipital bone free behind; 

 head long, broad, and flat ; mouth large, the lower jaw always the longer; anal 

 fin short, of 12 to 14 rays ; ventrals with 9 rays ; caudal fin truncate, its numerous 

 rudimentary rays recurrent above and below the caudal peduncle; number of 

 vertebras increased; body elongate, covered with thick skin Pelodichthvs. 



**, Adipose fin long and low, keel-like, aduate to the back, more or less perfectly con- 

 tinuous with the caudal fin; supraoccipital bone free behind; branchiostegals 

 9 ; anal fin short, with 11 to 20 rays ; caudal fin rounded, with numerous rudi- 

 mentary rays recurrent on the caudal peduncle; ventral rays usually 9; form 

 various, but body usually more or less elongate, depressed in front, compressed 

 behind, covered with a thickish but semi-transparent skin ; size small, NoxuKUS. 



CATALOGUE OF NOMINAL SPECIES, WITH IDENTIFICATIONS. 

 In the following list are given, in chronological order, the names thus 

 far proposed for our fresh-water Slluridce. In the right-hand column is 

 my identification of each species. Those species of which I have ex- 

 amined the original types are designated by a star (*). 



Nominal species. 



Date. 



Identification. 



Silurus catus, L 



1758 

 1817 



1818 

 1818 

 1818 



Amiurus catus. 



Silurus gyrinus, Mit . 



Notnrus gyrinus. 

 Ichthselurus punctatus. 

 Pelodichthys olivaris. 

 Noturus flavus. 



Silurus punctatus, Eaf 



Silurus olivaris, Raf 



Koturus flavus, Eaf 



