478 DR JOHN ALEXANDER SMITH ON CALAMOICHTHYS, 



region of pectoral fins, and becoming more compressed laterally, and tapering 

 slightly towards its caudal extremity. Caudal extremity, longer. (Scales gene- 

 rally smooth [?]) 



Fins, larger : — Pectorals, fin-rays osseous. Anal, apparently alike in size in 

 male and female. Ventrals, present. 



This new ganoid fish, from the great elongation of its body and the shortness 

 of its caudal extremity, must swim in a manner somewhat different from the 

 fishes of the genus Polypterus, and still more from that of ordinary fishes, whose 

 progression is due to alternate strokes or sweeps of the caudal extremity; 

 whereas in this fish, assisted by its very large and long swimming or air 

 bladders, it must be accomplished, as in eels and serpents, almost entirely by 

 alternate and successive lateral undulations of the whole body ; and the peculiar 

 character of its scales, which are comparatively small anteriorly, and enlarge 

 posteriorly, the posterior margin of each series of scales being free and projecting, 

 would also seem to assist in giving greater flexibility and force to these movements. 



The genus Calamoichthys agrees with the genus Polypterus, in the general 

 character of its numerous dorsal finlets; lobate pectorals; two nasal cirri; a 

 spiracle, or valve-like opening on each side of the head above, and a large flat 

 branchiostegal ray, or jugular plate, on each side of the mesial line below ; 

 and also in the hard, osseous, rhomboidal-shaped ganoid scales, arranged in rows, 

 running obliquely downwards and backwards; and in the tapering caudal 

 extremity of the body. 



It differs from Polypterus, however, in the various distinct peculiarities 

 which I have already enumerated, and especially in the great elongation 

 of its body and the total absence of ventral fins ; and these appear to be fully 

 sufficient to justify and confirm the propriety of its being placed in a distinct 

 and separate genus, to which, from the general lengthened and cylindrical form 

 of the fish, I have given the designation of Calamoichthys — (KaXayuo? and <x^' ? )- 

 The new genus belongs, therefore, to the same family as Polypterus, and would 

 accordingly fall to be placed next to the genus Polypterus, in the family of the 

 Polypterini. 



FAMILY POLYPTERINI. 



I. Genus POLYPTERUS. II. Genus CALAMOICHTHYS. 



1. Species C. calabaricus. 



Habitat, Old Calabar river, and the Bimbia, Camaroons, Western Africa. 



For the purpose of getting an anatomical description of this new fish, I 

 placed specimens, both of the males and the females, in the hands of Dr Ramsay 

 H. Traquair, Junior Demonstrator of Anatomy in the University, who has, 

 accordingly, prepared a detailed account of its anatomy.* 



* An abstract of Dr Traquair's paper is published in the Proceedings of the Royal Society of 

 Edinburgh, vol. v. p. 657. 



