1859.] On the Great Borqual of the Indian Ocean. 487 



But the lower jaw is remarkably slender for a Bal^enoptera, 

 even more so than in Baljgna mtsticettjs (as viewed laterally, 

 vide Oss. Eoss. pi. XXVI, f. 9) ; while the coronoid process is well 

 developed, as in Gray's figure of the lower jaw of Baljenoptera. ros- 

 trata (Zool. Voy. 'Erebus' and l Terror j Cetacea, pi. 2) ; the base of the 

 jaw, however, posterior to the process is not deeper as in that figure, 

 but the reverse, and the jaw is proportionally much longer anterior 

 to the process. The entire length of each ramus is within less than 

 2 in. of 21 ft., shewing the head to have been about a fourth of the 

 total length. Vertical diameter, 3 ft. in advance of summit of coro- 

 noid, 18 in. (measured by callipers) ; at 3 ft. from tip, 13| in. ; and, 

 where most contracted posterior to the coronoid, 15 in. only : ex- 

 treme depth, at coronoid process (inclusively), 26f in. From mid- 

 dle of coronoid to summit of condyle posteriorly, in a direct line, 

 37^ in. The shaft of the ramus is more approximative^ of the same 

 thickness throughout than in Bal^na mysticetus, tapering quite 

 evenly. 



The radius is 38f in. long, nearly similar in shape to — but more 

 curved than — that of Megapterapoeskop (Borqual du Cap, Cuvier, 

 Oss. Eoss. pi. 227, f. 22, c). The shape of this bone in Bal^ena 

 (as figured by Cuvier) is remarkably different. 



The rib is proportionally small, measuring only 8 ft. 2 in. round 

 its curvature to superior articulation. It is probably the third of 

 the series, on the right side. 



Of the five vertebrce, two are dorsal, about the 6th and 7th ; but 

 they have been much hacked and are mutilated of their processes. 

 Body of the vertebra (hind surface) \\\ in. deep by 15 in. broad. 

 A lumbar vertebra, probably the first, has the body (measured pos- 

 teriorly) 13| by 16^ in. broad ; antero-posterior diameter, 14 in. ; 

 spinal apophysis 27 in. (or a trifle more, allowing for the extreme 

 tip which is broken off), — measured from the front, and sloping back- 

 ward at an angle of nearly 45°.* Another lumbar vertebra, proba- 

 bly the 5th or 6th, with spinal apophysis 8 in. in antero-posterior 



* In the figure of the skeleton of the great Northern Borqual in the Volume 

 on Cetacea in Jardine's Naturalist's Library, pi. V, the apophyses of the dorsal 

 vertebra are represented to slope forwards ! 



3 r 2 



