fs'- 



rriE ANNALS 



AND 



ilAGAZIXE OF XATURAL UISTOUY. 



[EIGHTH SERIES.] 

 No. -47. XOVE^BER lOLl. 



L 



LXV. — The Classification of the Teleostean Fishes of the 

 Order Ostariophysi. — 2. Siluroidea*. Bv C. Tate Reg vn, 

 M.A. 



(Published by permission of the Trustees of the British Museum.) 



The Siluroids may be thus defined : — Ostariophysi with tlie 

 body naked or covered with bony plates, the mouth non- 

 protractile and the branchiostegal rays often numerous ; 

 parietals, symplectic, and suboperculum absent ; second, 

 third, and fourth vertebrae ankylosed to form a complex to 

 which the fifth is rigidly attached; parapophyses ankylosed 

 with centra ; epipleurals and epineurals absent. 



As in all Ostariophysi, there is no basisplienoid, but an 

 orbitosphenoid is always present ; the latter joins the frontals 

 above, the parasphenoid below, the lateral ethmoids in front, 

 and the alisphenoids behind. There is no opisthotic, but 

 the other otic bones are present ; the epiotics are rarely 

 prominent, but in the Doradidse they are important elements 

 of the cranial roof. The prseraaxillarics are typically fixed 

 but in the Callichthyidte and Loricariidse they are movably 

 articulated with the mesethmoid ; sometimes the toothed 

 praemaxillaries extend right back to the angle of the mouth 

 [Wallago, Ayeniosus, Aster ophysus), and the posterior exten- 

 sion may segment off as a distinct bone {Eutropiichthys) , 



* The Cyprinoidea have been dealt with in a separate paper, suprd, 

 p. 13. 



.4/271. <& Mog. N. Hist. Ser. 8. Vol. viii. 37 



