438 Dr. A. Gunther — Tertiary Fishes of Sumatra. 



and body, the position of the fins, the structure of the mouth, and 

 the number of fin-rays and vertebrae. With regard to its generic 

 affinity, I am guided in its determination chiefly by the form of the 

 head, and by consideration of the generic composites of the recent 

 fauna of Sumatra. All trace of barbels has disappeared : and the 

 j)haryngeal teeth are hidden in the confused mass of the crushed 

 bones of the head. 



The head is very long (7 inches), about -| of the length of the 

 vertebral column, formed of strong massive bones. The snout was 

 particularly long; the eye being situated nearer to the posterior 

 than to the anterior end of the head, close below the upper profile. 

 The maxillary, inter-maxillary, and mandible are strong bones ; 

 showing that the cleft of the mouth was of considerable width, but 

 did not extend to the eye. 



The vertebrae are higher than long, in fact, short. Eighteen 

 belong to the caudal portion of the column ; thirteen may be counted 

 between the attachment of the first interhsemal of the anal, and 

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

 the column apparently consisting of ten vertebra ; so that the total 

 number of vertebrae seems to have been about forty-one. The pro- 

 cesses and bony appendages of the vertebral column do not show 

 any peculiarity requiring detailed description. 



Neither the dorsal nor the anal fins are armed with an anterior 

 thickened spine. The former consists of three simple and nine 

 branched rays ; the longest of which is not quite half as long as the 

 head. The origin of this fin is considerably nearer to the root of 

 the caudal, than to the end of the snout, but little in advance of the 

 root of the ventral. Anal fin very short, about f as high as the 

 dorsal, consisting of three simple and five branched rays. Caudal 

 deeply forked ; the length of its lower lobe being about ^ of that of 

 the head. 



The pectorals are not well enough preserved to allow us to judge 

 of their length ; but the ventrals were evidently very well developed, 

 the length of their outer ray being nearly equal to that of the 

 largest of the anal fin. 



AmhlypJiaryngodon, Blkr. (PI. XV. Fig. 4.) 

 It seems that the existence of a large species of this genus is 

 indicated by a pair of pharyngeal bones, armed with globular molar 

 teeth in small number. On one of the bones three teeth are still in 

 situ, in a single series, the anterior being the largest, the middle 

 about, half as large, and the posterior minute. 



Chirocentrus (?) polyodon. (PI. XV. Fig. 3.) 

 Owing to its fragmentary condition, the determination of this 

 fossil is ver}'- uncertain. It appears to come nearest to Chirocentrus, 

 on account of the great development and form of the teeth of the 

 lower jaw, those of the upper jaw being much smaller. The whole 

 of the mandibulary series of teeth is preserved, with the anterior 

 half of the bone. Of the upper jaw only a fragment and an incom- 

 plete impression of the remainder is preserved. The mandibulary 



