266 



SILUEIDJE. 



2. ALLABENCHELYS. 



Bouleng. Proc. Zool. Soc. 1902, i. p. 234, and 1907, p. 1091. 



Characters of Clan'as, but casque less developed, the sides of the 

 head naked, only the postorbital shield being present. Dorsal and anal 

 reaching caudal. Vertebrae 68-70. 



Two species : — 

 Depth of body 7-8^ times, head 5-5^ times in total 



length 



ventrals l^-lf as distant from root of 



caudal as from end of snout ; D. 65-75, A. 60-65. 1. A. brevior, p. 266. 

 Depth of body 9-12 times, head 5^-6 times in total - , 



length; ventrals l|-2 as distant I'rom root of 



caudal as from end of snout; D. 80-90, A. 60-75. 2. A. longicauda, p. 267. 



1. ALLABENCHELYS BREVIOR. 

 Bouleng. Ann. & Mag. N. H. (7) xii. 1903, p. 439, and Proc. Zool. Soc. 1907, 

 p. 1091, fig. 

 Depth of body 7 to 8^ times in total length, length of head 5 to 5^ 

 times. Head 1|- to 1^ times as long as broad, smooth above, the bony 

 casque, in the middle of the head, about ^ width of head ; postorbital 

 bone narrow ; occipital process acutely pointed ; a small frontal 

 fontanelle ; occipital fontanelle a little smaller, partly on occipital 



process ; eye very small, 2^ to 3 times 

 in length of snout, 5 to 6 times in inter- 

 orbital width, which is f length of head ; 

 band of prajmaxillary teeth 3 to 4 times as 

 long as broad; vomerine teeth conical 

 or subgranular, forming a crescentic 

 band which is as broad as or a little 



Fio-. 221, 



A llahenchehjs brevior. 

 Type (P. Z. S. 1907). 3. 



broader than the pra^maxillary band ; nasal barbel f to f length of 

 head ; maxillary barbel as long as or a little shorter than head, not 

 reaching beyond middle of pectoral fin ; outer mandibular barbel | to J 



