DE. J. MURIE ON THE POEM AXD STRUCTUEE OF THE MANATEE. 163 



attachment ; both pass round the vagina towards the clitoris, partially decussating with 

 the fibres of the sphincter vaginse. 



In the male, as Vrolik' more particularly has noted and figured, there is a well- 

 defined fleshy ischio-cavemosus and long retractores j^enis. Moreover I readily recog- 

 nized a bulbo-cavernosiis. While fully developed and normal in attachment, these 

 thi-ee muscles correspond with the somewhat altered position of the pelvis &c. from 

 that of quadrupedal Mammals. 



3. Muscles of the Dermis. 



The supei-ficial fleshy investment to which the name of jyanniculus carnosus has been 

 given, is enormously developed in the Manatee. Indeed, as Stannius justly observes, the 

 ventral portion of it represents in a certain degree a supplementary belly-muscle, sup- 

 plying the voluminous entrails with an additional powerful support, which is so much 

 needed owing to the extraordinary shortening of the rib-cartilages. In the female, as 

 also to some extent in the younger male, the depth of muscle varied in different regions. 

 The muscular fibre in the former specimen, at its posterior abdominal or genital portion, 

 had a thickness of 1^ inch ; but further forwards, towards the middle of the body, it 

 decreased to 0"6 inch, thinning upwards on the back to 0'2 inch or thereabouts. On 

 the side of the neck it equalled the midventral part in volume, thickening considerably, 

 however, on the side of the cheek. 



Although the panniculus forms a uniform whole, I shall prefer, for several reasons, 

 to describe it piecemeal. 



As indicated above, the extensive panniculus carnosus forms a great broad fleshy 

 wrapper of longitudinally directed fibres, covering the entire abdominal surface (P.c') 

 from the pectoral limbs backwards to beyond the anus (P.c***). On the side of the 

 posterior half of the body the muscle stops short of the tips of the ribs, where part of 

 the external oblique is exposed ; but forwards from this it rises higher, the fleshy 

 part reaching almost to the level of the vertebral border of the scapula. The line of 

 demarcation of this lateral or costal border, however, is not so abrupt, as exhibited in 

 fig. 8, PI. XXL, but trends, and is lost dorsalwise in a strong aponeurotic fascia. The 

 muscular fibres of the outer shoulder portion pass forwards along the neck and side of 

 the cheek, and partly become inserted by aponeurosis on the broadest surface of the 

 malar bone, and, partly fleshy, are continued onwards and commingle behind the angle 

 of the mouth with a deeper throat-layer of the muscle presently to be desci'ibed. 



A few inches behind the axilla the belly portion of the panniculus splits into two 

 segments, the outer or upper fork of which is that already spoken of as covering the 

 outer surface of the shoulder. From this a slip runs towards the humerus (P.c*). 



The inner sternal fork, at its divarication, possesses an external tongue-shaped corner 

 (P.c**), mesially to which the muscle lies over the sternum (in the female being 

 ' Bijdragen, p. 77, pis. 5 & 6. figs. 22, 23, b, d. 



