196 



CrPBIKlD^E. 



of the anterior arch in B. hynni and allies, very short, knob-like, and more widely 

 spread, 6 to 8 in number on the lower part of the anterior arch, in B. perince and 

 other small species. 



Tig. 23. 



A - J*. a 



Scales of (A) B. hynni, (B) B. joileurogramma, (C) B. perince, 

 from the middle of the side, enlarged. 



The lower pharyngeal bones and their teeth differ little according to the species ; 

 the number of teeth is normally 10, viz., 5 in the inner row, 3 in the median row, and 

 2 in the outer ; in one specimen of B. leptosoma, however, there are 3 teeth in the 

 outer row (see PI. XXXVII. fig. 5). The second tooth of the inner row is always the 

 largest, and frequently molariform or mamilliform. The only point calling for notice 

 as a specific character is the much larger size of these pharyngeal bones in B. surkis 

 than in the other species, a difference that may be realized by the following 

 measurements (in millimetres) of two adult specimens : — 



B. hynni. B. surlcis. 



Length of head 92 97 



Width of head 63 60 



Length of pharyngeal bones * 30 40 



Greatest width of pharyngeal bones 41 58 



The bones of which these measurements are given are figured on PL XXXVII. 

 figs. 3 & 4, as seen from above and behind. 



The skull is moderately massive ; a supraorbital bone is present, but does not reach 

 the postorbitals ; the occipital crest is short and low and does not encroach on the 

 parietals, which bear a transverse ridge. The prsemaxillaries have short, median 

 ascending processes, and the maxillaries are produced into a short posterior process. 

 The clavicles and coracoids are moderately developed. The vertebrae vary in number 



* Measured from the extremity of the symphysis to the level of the crowns of the hindermost teeth. 



