The Skull of the Manatus Senegalensis and Manatee. 261 



se tabling so closely, in that state, the larva of the common 

 Cheimatobia brumata, as to be almost ^indistinguishable. 



II. Remarks on some Comparative Anatomical Distinctions between the 

 Skull of the Manatus Senegalensis and that of a Manatee from the 

 Bay of Honduras. By James M'Bain, M.D., R.N. (Specimens 

 exhibited.) 



The skull of a Manatee from the Bay of Honduras, which 

 I now exhibit to the Koyal Physical Society, was presented 

 to the Hunterian Museum of Glasgow about seventeen years 

 ago, along with a considerable portion of the skeleton, by 

 Mr James Banks, late of Belize, Honduras, but latterly re- 

 siding at Prestonpans.* 



In the remarks which I shall have occasion to make on 

 this skull, it will be necessary to refer to the " Notice of a 

 Skull of a Manatee from Old Calabar," which I read at a 

 meeting of the British Association at Aberdeen in Septem- 

 ber 1859, and which was published in the Proceedings for 

 that year. 



In the skull from Old Calabar, which I have brought here 

 for comparison, the occipital bone, petro-mastoid, and tym- 

 panic bulla, are wanting ; and in the skull from the Bay of 

 Honduras there is a transverse section at the base of about 

 an inch in breadth, extending across between the tympanic 

 bones, which involves the loss of nearly the whole basi- 

 occipital. It is in this lost part that several of the princi- 

 pal foramina at the base of the skull are situated. 



That portion of the crista interna formed by the inner 

 tables of the frontal bone, extending upwards and back- 

 wards from the largely developed crista galli of the ethmoid 

 in the skull from Old Calabar, is almost wanting in the 

 skull from Honduras. The parietal part of the crista in- 

 terna in the latter skull is well-marked, increasing in size 

 backwards until it expands into a large internal occipital 

 protuberance, with a broad transverse ridge which separates 

 the cerebrum from the cerebellum. The palate of the skull 

 from Honduras, measured from the incisive edge of the pre- 

 maxillary bones to the posterior part of the spinous cleft of 



* I regret to see a notice of Mr Banks's death in the " North British Ad- 

 vertiser," as having occurred at Prestonpans on the 6th instant. 



