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



form and arrangement, I am obliged to refer these remains to a 

 distinct genus. 



The pharyngeal bone is of the usual shape, 26 millim. long, 

 armed in its concavity with a single series of three large teeth, 

 each of which differs from its fellows in form. As isolated teeth, 

 but of much larger size and more perfect, are available for examina- 

 tion, I take the description from them. 



The hindmost tooth is of conical shape, with the aipex excentric, 

 directed towards the second or middle tooth. The greatest diameter 

 of its base is 10 millim. long, the transverse diameter 8, and this 

 is also its height. It reminds us in its general form of that common 

 shell, Lepeta ccsca. The second tooth has more the shape of the 

 molar of a carnivorous animal. On its crown it is provided with 

 three tubercles, or rather with two longitudinal ridges, of which 

 the outer one is divided by a notch into two tubercles, the more 

 prominent of which is that nearest to the first tooth. This tooth is 

 9 millim. broad, 6 long, and 9 high. The last tooth is the smallest, 

 much compressed in the longitudinal axis of the dental series. Its 

 upper surface is much ground down, it is only 5 millim. high and 

 4 wide. A comparison of these large teeth with those attached to 

 the pharyngeal, shows that this Cyprinoid must have attained to as 

 great a size as any of the living species ; the pharyngeal may have 

 belonged to a fish 10 inches long. 



Besides this fish, there are from the same deposits several dorsal 

 and pectoral spines, evidently belonging to the Siluroid described 

 above as Pseudeutropius verbeeMi ; also some isolated Cyprinoid 

 bones, which, however, are of too general a type to be specifically 

 determined, or to require more than this passing notice. 



Finally, I have to add that Dr. W. v. d. Marck describes and 

 figures the posterior portion of a vertebral column under the name 

 of BracJiyspondylus saropterix. It appears to me to have belonged 

 to a Cyprinoid fish, but I would not venture to define more nearly 

 its affinities. The presence of nine branched rays in the anal fin 

 may serve as a guide as regards the group, to which this fish ought 

 to be referred. 



EXPLANATION OF PLATES XV.-XIX. 



Auliscops sumatranus, Gunther. 

 Fseudeutropius verbeekii, Gunther. 

 Chirocentrus (?) polyodon, Gunther. 

 Amblypharyngodon, Blkr. 

 Bagarius gigas, Gunther. 



Hexapseplnis^ sp. nat. size, pharyngeal bone, with three 

 teeth in situ. 

 ,, Za. Hexapsephus, pharyngeal teeth. 



n 3d. ,, „ 



>J ^^' ■)■> >> 



XVII. Thynnichthys amblyostoma, Marck, sp. (This figure is drawn from 

 two examples as indicated by the line of fracture.) 



XVIII. Barbiis megacep)halus^ Giinther. 



XIX. Notopterus primcevus, Gunther. 



Plate XV. 



Fig. 1. 





» 2. 





„ 3. 





„ 4. 



„ XVI. 



„ 1. 





„ 2. 



