200 CRESTED SEAL. 



subjoin some interesting particulars which are ap- 

 pended by Drs Ludlow and King to Dr Dekay's me- 

 moir. Their account of the sac-like crest is as 

 follows : " About two inches from the extremity of 

 the upper jaw, on the superior surface, arises a car- 

 tilaginous crest, rapidly increasing in height, as it 

 passes backwards, being about seven inches in 

 height at its posterior or vertical edge, which is se- 

 parated into two planes by an intervening depression 

 of an inch in depth. Its superior edge is slightly 

 convex, and the whole structure is clearly an elonga- 

 tion of the septum of the nose, the true nostrils 

 opening on each side of it by an oblong fissure. 

 This crest runs into the hood or sac-like appendage 

 of the head. This hood is strongly muscular, with 

 an aggregation of circular fibres round its external 

 orifices, which are two, situated at the lower ante- 

 rior part of the head. These probably served the 

 purpose of sphincters, so as perfectly to close the 

 sac. The length of the upper jaw beyond this 

 crest is chiefly attributable to the intermaxillary 

 bones, which are long and broad." 



The following is their interesting account of the 

 eye: " The eye is very peculiar, perfectly spherical, 

 with the nerve entering directly in the axis of the 

 ball. The sclerotic or external covering is divided 

 at its middle entirely round ; its two edges being 

 connected by an elastic membrane thickly covered 

 by muscles. The posterior half is subdivided into 

 four longitudinal segments, extending from its edge 

 to within a quarter of an inch of the entrance of 



