59. ARics. 1^9 



I have observed in several species that the bands of teeth on the 

 palate become relatively larger with age, so that the vomerine teeth, 

 wliich in young specimens form a slightly iaterrupted band, are 

 confluent into one band in others which are more advanced in 

 growth ; in the same way the palatine teeth may be entirely united 

 with those on the vomer, or separated by a narrow interspace. In 

 species which have rudimentary vomerine teeth, these are sometimes 

 entii-ely lost with age. 



Synoj)sis of the S2}edes. 



I. The vomerine teeth are present, and form one continuous or but slightly 



interrupted band, which is more or less confluent with the palatine 

 teeth. 



A. Teeth on the palate villiforni. 



«. East Indian species : Hexmietnatichthys, Blkr., p. 139. 



b. South American species : Guiritinga, Blkr. + Sciades, Blkr., 



p. 143. 



c. African species, p. 151. 



B. Teeth on the palate gi-anular, p. 152. 



II. Teeth on the palate in two generally widely separate patches ; some- 



times the vomerine teeth are present, but widely separate into two 

 small groups which may be continuous with "the palatine teeth : Ariu^, 

 ^'alenc. 



A. Teeth on the palate villiform. 



rt. A Large intemeiual shield on the nape : Arius, sp., Blkr., p. 153. 

 b. No large mternem'al shield on the nape. 



a. African species, p. 154. 



^. South American species, p. 155. 



y. Pacific species, p. 157. 



S. East Indian species : Hemiarius, Arius, C'ephalocassis, et 

 Ketiana, Blkr., p. 158. 



B. Teeth on the palate granidar or obtusely conical. 



a. Teeth on the palate in four groups, those of the vomer being 



present : Armies, sp., M. & T., p. 163. 



b. Teeth on tlie palate in two groups : Pseudarius, Blkr. 



a. East Indian species, p. 166. 

 fi. American species, p. 171. 

 Appendix : Bagrus venaticus et B. veiiagn^, p. 174. 



I. The vomerine teeth are present, and form one continuous or but slightly 

 interrupted band, which is more or less confluent ^\'ith the palatine 

 teeth. 



A. Teeth on the palate villiform. 



a. East Indian species. 



1 . Arius thalassiuus. 



Deddi jella, Rum. Fish. Coram, pi. 16S>. 



Bagrus thalassimis, Riipp. X. W. Fischc, p. 75. taf. -0. lig. -. 



bilineatus, Cuv. iV Val. xiv. p. 434. 



