Dr, A. Gunther — Tertiary Fishes of Sumatra. 437. 



large and firm opercular bones ; a short dorsal fin, without osseous 

 spines, and opposite to the ventral fins ; a short anal ; compressed 

 pharyngeal teeth in three series, and truncated at the top. Such 

 are the characters of this genus which we may expect to be 

 visible in fossil remains, and in which, indeed, the fossils before us 

 agree with the recent species of Thynmchthys. The peculiar shape 

 of the mouth of the latter is, however, entirely destroyed in the 

 fossils. 



The following parts can be more fully described. The head was 

 large, its length being considerably more than one-half of the length 

 of the vertebral column. The lower jaw was obliquely directed 

 upwards. The margin of the prseoperculum, which was not covered 

 by the skin, is wide, deeply ribbed with muciferous channels, radiat- 

 ing towards the edges. The upper and lower limbs of this bone are 

 equal in length, and meet at a right angle, which, however, is 

 rounded off. Operculum very large, striated in its lower half. 



As regards general structure, the vertebrae do not differ from those 

 of the genus Barbus, those in the middle and posterior portions of 

 the column being rather deeper than long. Fifteen or sixteen belong 

 to the caudal portion of the column ; thirteen or twelve may be counted 

 between the first attachment of the interhaemal of the anal and that of 

 the first interneural of the dorsal fin ; the foremost part of the column 

 apparently consisting of seven or eight vertebrae, so that the total 

 number of vertebrae does not seem to have exceeded thirty-six. The 

 neurals of the anterior vertebrae were of moderate strength and 

 height (18 millimetres), equal in length to three and a half of 

 the middle vertebrae. The scleral spines were numerous, forming 

 bundles attached to the middle of the neurals and heemals of the 

 caudal vertebrae, and lying in the direction of the longitudinal axis 

 of the body. The ribs do not show any peculiarity as regards form 

 or size. 



The dorsal fin consists of three simple and nine branched rays, 

 the third and fourth rays being the longest, about two-thirds the 

 length of the head ; its origin falls vertically before that of the 

 ventrals, nearly midway between the end of the snout and the root 

 of the caudal rays. Anal very short, and only about two-thirds as 

 high as the dorsal ; it consists of three simple and five branched 

 raj^s. Caudal fin deeply forked ; the length of the upper lobe being 

 not much less than that of the head. The pectorals appear to have 

 extended to, or nearly to, the root of the ventral fin. 



In one specimen only remains of the pharyngeal apparatus could 

 be found. They are in situ, and consist of three polished closely 

 adpressed laminjB, in which the crown is still cutting, not worn 

 down by use. 



This fish has been described and figured by Dr. W. v. d. Marck 

 as a Clupeoid, Sardinioides amblyo stoma. However, there can be no 

 doubt as to its belonging to the CyprkiidcB. 



Barbus megacephalus. (PL XVIII.) 

 This fish is represented by a single specimen, 23 inches long. It is 

 sufficiently well preserved to ascertain the general form of the head 



