172 DE. J. MUEIE ON THE FOEM AJSTD STEUCTUEE OF THE MANATEE. 



narrower, expansion. The first is very glandular, and with convolute rugae ; the second, 

 thinner walled, assumes interiorly the character of the rest of the great intestines. 

 These in the female, including csecal appendage, are 17 feet 9 inches long, and in the 

 male 18 feet — the greater muscular contraction of the former probably accounting for 

 the difference. The rugse are very numerous, close-set, and chiefly longitudinal, and 

 obliquely interdigitate, forming shallow elliptical depressions, among which are glan- 

 dular patches. Halfway on the gut the rugae and glands diminish in size and number. 



To supply a desideratum as regards the abdominal viscera in their natural position, I 

 have given in fig. 20 a reduced copy of a diagrammatic sketch taken from the young 

 male animal. It represents the parts as seen when a median longitudinal section has 

 been made from near the anus forwards to the middle of the sternum, the fleshy walls 

 being dragged outwards. Anteriorly the heart appears to occupy the full breadth of 

 the chest, the severed pericardium stretching across at its bifid apex. Behind is the 

 liver, segmented into four divisions, — a very large triangular portion of the right and 

 another equal-sized portion of the left lobe filling respectively the right and left sides 

 of the cavity ; whilst between them, in the triangle bounded by the pericardium and 

 their anterior borders, are two much smaller lobes, the right one of which contains the 

 rather large gall-bladder. No lungs or diaphragm are exposed, the apparent and not 

 real absence of the latter doubtless having deceived Dr. G. A. Perkins' in his examina- 

 tion of Wyman's^ Manatus nasutus. Mesially situated and betwixt the hinder fork of 

 the great liver-masses, a small piece of the stomach and curved appendix are exposed. 

 The remaining posterior half of the abdominal cavity shows only intestinal coils, and 

 partially the urinary bladder when this viscus is distended. 



When, however, the thoracico-abdominal cavities with the entrails in situ are 

 examined sidewards, a representation of which has been given in the body-section 

 (fig. 37, PI. XXVI.) with the ribs in place and the intervening tissues removed, a 

 widely difierent view is obtained. The relations of the parts mentioned (heart, liver, 

 intestines, and bladder), to some extent, remain good. But above them is brought out 

 in relief the enormous lung, which reaches from the first to the last rib, and extends 

 more than midway downwards, just permitting a fringe of the elongated diaphragm to 

 peep through below and be the barrier line betwixt the dorsal pulmonary and ventral 

 cardo-alimentary compartments. 



3. Glands concerned in Digestion. 

 Of the secretory apparatus connected with the mouth, the most conspicuous bodies 

 are the parotid glands. As briefly noted by Stannius, these are very large and lie at 

 the sides of the lower jaw. They have a coarse granular texture, are broad and flat, 

 and reach from the insertions of the cephalo-humeral and levator claviculi muscles 

 forwards to beyond the angles of the mandible. In the vertical and horizontal direc- 

 ,... ' Proc. Boston Soc. Nat Hist. (1845-48) vol. ii. p. 198. ^ Ibid. vol. iii. p. 192. 



