170 PROFESSOR STRUTHERS. 



level with outer margin of beak, in Megaptera, width 8 inches, 

 depth 1; in B. musculus, width 12f inches, depth 2. 



Seen in profile, the lower edge of the median beam of the 

 palate is less curved in Megaptera ; depth of concavity in Megap- 

 tera 3 inches, along the maxillary part only, 2 inches ; depth in 

 B. musculus 4 inches, along the maxillary part only, 2 inches. 



The breadth of vorner exposed between the lower edges 

 of the maxillaries is, in Megaptera about 1J inch all along, 

 except about the middle when it is increased to 2 J inches ; 

 behind, between the palatals, J inch in vomer is seen, increasing 

 forwards. In B. musculus, along the anterior half, about J inch, 

 on the posterior half, f to 1 inch in breadth of the vomer is 

 seen. The bony vomer extends to within 27 inches of the point 

 of the beak in Megaptera, to within 15 inches in B. musculus. 



21. VASCULAR GROOVES ON THE PALATAL SURFACE OF THE 

 MAXILLARY BONE. This system of great palatal grooves, and 

 their foramina, will be better understood by observing them 

 first in B. musculus. They are great grooves f to J inch broad, 

 such as might be made with the end of the finger on a soft 

 surface. They may be classified as (a) those of the roof, belong- 

 ing to the whalebone region, and (b) those of the median beam. 

 Those of the latter (b) issue from the fore-end of the palato- 

 maxillary fissure, at least 3 in number, descend along the beam 

 with more or less obliquity, one of the three arched up and 

 covered for a time on the right side, on the left side two are 

 thus arched and covered. The most anterior one reaches the 

 lower edge of the beam at about the middle of the second 

 quarter of the beak, and ceases at the middle of the beak. 

 (a) Those of the whalebone region may be classified as anterior 

 or longitudinal, seen on more than the anterior three-fourths of 

 the beak; the intermediate, seen on the posterior half of the 

 first quarter of the beak ; and the posterior, seen below the 

 temporal fossa. Of the anterior or longitudinal series, three 

 issue on the anterior half of the first quarter of the beak, the 

 external first, the third at the end of the first quarter, a fourth 

 some way along the second quarter. The two last of these run 

 along the inner part of the roof, where the roof meets the median 

 beam, close together as great grooves, half an inch in breadth 

 and deep enough to receive half the thickness of the finger, the 



