of the Skeleton of BalcenSptera Rorqual. 225 



muzzle or extremity of the palatine bones ; and posteriorly 

 by the vault of the skull, which is occupied by the brain, and 

 is distinguished by the frontal bone, which, passing in a semi- 

 lunar direction, terminates in a process that contributes 

 to form the anterior portion of the zygomatic arch ; thus 

 exhibiting an analogy to quadrupeds. From the top and 

 anterior part of the frontal bone the nasal bones are articu- 

 lated by sutures, and extend the whole length of the upper 

 part of the mouth. Beneath these are two vomeres [plough-- 

 share bones], forming two thin osseous laminae, and these are 

 closely connected to the inferior part of the frontal bone. 



The superior surface of the palatine bones may be perceived 

 externally, and they are of a more spongy texture than the 

 preceding. They are of a ti'iangular form, and are curved 

 at the external margin. Towards the posterior part there 

 are five or six large foramina [orifices], which afford a pass- 

 age for the nutritive arteries, &c. Between the above bones 

 there is a large space left in the upper part of the mouth, 

 which affords a lodgment to the ethmoidal bone [a bone that, 

 in the superior part of the human nose, resembles a sieve]; and 

 also for the spiracles, through which the animal ejects water ; 

 and these are popularly denominated the blow-holes. The 

 ethmoidal bone is placed in the cavity formed by the nasal 

 bones, and by which it is concealed : it is light, spongy, and 

 formed of thin laminae. 



The lateral surfaces of the skull are likewise nearly trian- 

 gular, and extend superiorly only to the sides or parietes 

 [walls] of the nose ; presenting several furrows which afford 

 a lodgement to sevei-al important blood-vessels and nerves. 

 The use of these bones is to augment the nasal cavity ; they 

 are lined by a dense, thick, olfactory membrane, in which the 

 organ of smell is situated. 



The inferior surface, like the rest, is triangular, and is 

 mostly formed by the principal part of the palatine bones, 

 and likewise possesses a great number of furrows and canals 

 which afford a passage to the nutritive vessels and nerves ; 

 in the exterior boundary there is a sulcus [furrow], which 

 indicates the place where the baleen or whalebone is inserted. 

 At the posterior part of this surface, and between the mastoid 

 processes [processes of the neck bone, shaped like the nipple 

 of the breast], the two bones containing the organ of hearing, 

 denominated the petrous, or, as I term them, the acoustic 

 bones, are placed. In the interior there is a nervous pulp, in 

 which the sense of hearing is supposed to reside. 



The posterior surface or base of the skull is of a semicir- 

 cular form, with two large alae or wings on its sides, ^t the 



Vol. V. — No. 25. q 



