ANATOMY OF MEGAPTERA LONGIMANA. 183 



posterior open in the lower part of the groove. The groove is 

 not large, wide enough only to lodge the side of the little finger, 

 about 'l to ^ inch deep, and is formed rather of a succession of 

 short grooves continued from the foramina. 



[In 7>. rmiscuhis the internal series do laot begin till about 15 inches 

 in front of the coronoid process, the groove 4 inches earliei*. There- 

 after there is a continuous groove, formed as in Megaptera, receiving 

 the successive foramina, altogether about 20 in number. There is 

 no wide interval, as thei'e is in Megaptera, between the first group of 

 foramina and those anterior to them. The groove and its foramina 

 are at first rather nearer the border (1^ inch from it) than in Megap- 

 tera, but in B. musculus additional foramina occur farther down. 

 These (2 on the left side, 3 on the right) open at 15 to 23 inches in 

 fi'ont of the coronoid process, bi inch below the general groove. From 

 each of these a deep groove, wide enough to receive a goose-quill, 

 passes obliquely forwards to enter the general groove, after a course 

 of 7 to 12 inches. The most posterior on the right side again enters 

 the bone, for 3 inches, before it ends in the general groove. These 

 long oblique grooves form a striking distinction of B. musculus from 

 Megaptera.] 



The external series of foramina are of much greater size, 

 enough to admit a finger somewhat flattened ; the internal series 

 vary in size between that of a goose-quill and crow-quill. In both 

 Megaptera and B, musculus the external series are about 6 in 

 number (6 on the right side, 7 on the left, in both), but in 

 Megaptera they do not begin so soon, and are continued farther 

 forwards. The distance of the first from the coronoid process is, 

 in Megaptera 82 inches, in B. musculus 24 inches. Thus the 

 internal series begin earlier in Megaptera than in B. musculus ; 

 the external series the reverse. The distance of the last of the 

 external series from the symphysis is, in Megaptera 28 to 30 

 inches, in B. musculus 35 to 38 inches. Owing to their late 

 beginning in Megaptera, the foramina are closer together than 

 in B. musculus. In Megaptera they extend over a distance of 

 35 to 39 inches ; in B. musculus a distance of 54 to 58 inches. 

 They occur at intervals of 6 to 7 inches in Megaptera, of 9 to 10 

 inches in B. musculus, but with some variation. They are 

 broader and flatter in Megaptera than B. musculus. 



At 13 inches from the symphysis (8 to 10 in B. musculus) the 

 dental canal is unroofed by a fissure | inch wide all along in 

 Megaptera, much narrower behind in B, musculus. In both the 



