166 PROFESSOR STRUTHERS. 



17. ANT-ORBITAL PROCESS OF THE MAXILLARY. The great 

 length and backward and downward sweep of this process from 

 the beak in Megaptera is characteristic. Length of process 

 from beak 18 inches, with a fall of about 12 inches ; in B. 

 musculus length about 15 inches, less as seen in front, with a 

 fall of about 6 inches. The form also is different, prismatic in 

 Megaptera, flat in B. musculus. In B. musculus, where the 

 process goes off, the curved border of the temporal fossa rises 

 into a tubercle 2 inches high, 3 inches broad at the base. The 

 border then twists forwards soon, overlapping the border from 

 the beak, and forms the anterior edge of the flat process. This 

 is the result of the forward extension of the temporal fossa in 

 B. musculus. In Megaptera the prismatic form is owing to a 

 lamina rising upwards and backwards, the edge of which is 

 continued from the front edge of the temporal fossa. This 

 lamina is represented in B. musculus by a low smooth ridge on 

 the flat temporal fossa surface of the maxillary at 3 inches 

 behind the anterior border of the process, while the tubercle in 

 B. musculus is represented in Megaptera by a sharp even ridge 

 running along the facial surface of the process. The outer end 

 of the process in Megaptera is, in length externally, in front of 

 the malar, 3 inches ; in breadth, within the orbit, 6 inches ; in 

 B. musculus length 4 J inches, breadth within the orbit 6 inches. 



The overlapping of the fronted by the maxillary is greater 

 in Megaptera ; breadth of the part overlapped 7 to 8 inches, 

 bevelled marking on frontal 3 inches in length, but only 2 inches 

 of it covered by the maxillary. In B. musculus breadth of 

 angle overlapped 6 inches, the length overlapped 2 inches ; no 

 bevelled marking on frontal. Length of maxillary uncovered 

 by frontal in temporal fossa, in Megaptera 1 inch, in B. mus- 

 culus 4 inches. The ant-orbital process is in Megaptera 1 to 1 J 

 inch behind the frontal process ; in B. musculus 9 inches in 

 front of it. 



18. THE BEAK. A survey of the beak from before at once 

 shows the well-known greater breadth, with more convex edges, 

 in Megaptera, contrasting with its long tapering form in B. 

 musculus. The actual length in Megaptera is 85 inches, in B. 

 musculus 96. It is convenient to divide the beak into quarters. 

 At the base of the beak the breadth, along the curve, is less in 



