DESCRIPTION OF A LITTLE KNOWN AGONOID FISH, 

 HIPPOCEPHALUS JAPONICUS. 



With Plate X. 



BY FRANK CRAMER. 



But two specimens of this little known species seem to 

 have been previousl}^ recorded: one, picked up by Stel- 

 ler on the shore of one of the Kurile Islands in June, 

 1743; the second, secured by Tilesius in the Gulf of Pa- 

 tience, Island of Segalien, July 30, 1805. Steller's spec- 

 imen, preserved in a dried condition, was forwarded to 

 St. Petersburg to become the type of Pallas' Cottits j'a- 

 ponicus. The second specimen, at tirst considered iden- 

 tical with Cottics japontcus, was afterwards separately de- 

 scribed by Tilesius under the name Agoutis stegophthal- 

 inns. Of the latter, Tilesius has left several descriptions 

 and figures (see synonymy) which are unfortunately dis- 

 cordant in many of their details. 



Subsequent writers have added little to the history of 

 the species. The types of japo7iiais and stegophthahnus 

 seem not to have been re-examined or compared, but Cu- 

 vier and Valenciennes, after a careful review of the pub- 

 lished figures and descriptions, decided that stcgophthahnus 

 3.nd japoiiictis were identical, and needlessly proposed for 

 the species a new name, superciliosus. In 1839, Aspidof ho- 

 rns super ciliosus, Aspidophoriis qiiadricornis and Agoniis 

 decagonus were ranged by Swainson in a new genus, for 

 which he proposed the name Hippocephaliis. Needless 

 to say, his generic characterization is worthless, and the 

 three species therein included are not congeneric, deca- 

 gonus belonging in fact in an entirely different part of 

 the family. As the species superciliosus {= japoiiicus) is 

 mentioned by Swainson first, it has been customary to 

 consider it the type of the genus. Characterizations of 



2d Ser., Vol. IV. Mav 0, 1894. 



