180 DE. J. MUEIE ON THE FOEM AND STRUCTUEE OF THE MANATEE. 



putably traced from origin to insertion ; the anterior remnant remained, its posterior 

 fibres being lost among the tangled vessels and deep cervical fascia. Stylo-hyoid and 

 stylo-pharyngeus are somewhat adherent, the latter broad and well developed. The 

 digastric, single-bellied and broad anteriorly, fills the hollow at the inflection of the 

 mandible, and thence passes rearwards to the junction of the stylo-hyal with its cranial 

 cartilage. The horseshoe-shaped submaxillary gland abuts on its inner, and the parotid 

 on its outer margin. The stylo-glossus is large, and the constrictores superior and medius 

 are full and fleshy. The thin sheet of fibres of the levator palati cover the Eustachian 

 enlargement, and are spread out and lost in the posterior palate. The tensor palati, 

 better marked, arises near the tympanic bulla, passes round the pterygoid process, and, 

 by a strong flat tendon, widens out on the posterior palatal membrane. The pterygoidei 

 and plexuses lie outside. The palato-glossus is moderately broad, and the palato- 

 pharyngeus fairly developed. Mylo-hyoidei, as a thin fleshy plane, stretch and fill the 

 angle betwixt the ramal bodies. Long and thin genio-hyoidei pass from the basihyal 

 to the concavity of the chin, a vascular plexus existing beneath. A distinct hyo-glossus 

 was not observed ; but genio-hyo-glossi and lingualis are both well represented. 



VIII. The Nervous System. 



When treating of the interior of the skull I dwelt upon the dura mater as it lines 

 the bones and the foramina piercing it basally. Its upper surface, when the calvarium 

 is removed, is tolerably smooth, a superior longitudinal sinus being but faintly indicated. 

 On each side the membrane is tucked into a deep Sylvian sulcus, which traverses well 

 across the cerebrum ; another, marked but shallow, depression is manifest about the 

 centre of the posterior cerebral division. The dura mater is tough, strong, and rough at 

 the vascular sinuses and plexuses. While it is intact, the cerebrum leaves the bulging 

 cerebellum uncovered to a considerable extent. 



The encephalon of the younger male was so destroyed as to be unfit for examination. 

 While the membranes surrounded the brain of the female specimen a tolerably accurate 

 idea of the cerebral contour was got ; but on raising the dura mater the brain itself was 

 found to be softened, nnd with difiiculty extracted. No measurements or weight were 

 taken, but the whole placed in spirit as rapidly as possible. A cast of the cranial 

 cavity with its enclosed dura mater was subsequently made ; and by the help of this 

 cast and the shrunken brain the sketches (PI. XXV.) were drawn. 



I may remark, en passant, that the views (figs. 31 & 33) of the upper and under surface 

 of the brain slightly exaggerate the relative breadth of the anterior to the posterior 

 lobes, by the former not being approximate enough at the longitudinal fissure. With 

 regard to dimensions, the drawings are given as nearly as possible of the size of nature ; 

 the cranial interior, its model, and the preserved brain respectively yielding the scale 

 of relations. 



From above and below, the outline of both cerebral hemispheres is somewhat qua- 



