32 



feet, when the transverse folds gradually disappear, and the longitudi- 

 nal disposition predominates through the remainder of the smallintes- 

 tines. The ■vvhole length of this part of the canal, in the Dugong lašt 

 dissected, was twenty-seA'en feet ; the diameter of the canal uniformly 

 about one inch. The muscular coat throughout, two and a half lines 

 thick, the external longitudinal layer being half a line in thickness. 

 The cellular cr nerv'ous and mucous coats together ■vvere two lines in 

 thickness. The orifices of the intestinal glands describedby Home, 

 (ut sup. p. 318,) were very distinct in the lirst specimen dissected, 

 arranged in a zig-zag line— thus .•.•.•.•. • — upon the Tnucous 

 membrane, along the side 6i the intestine next the mesentery, and 

 occasionally crossing from one side to the other of the line of attach- 

 ment ; they were continued all the vay to the cacum. 



" It would seem that this appendage was present in all the her- 

 bivorous Cetacea ; Steller describes it as of large size, and sacculated, 

 in the Northern Manatee (S tellerusy Daubenton has given afigure 

 of the bifid ctecum in the Southern Manatee (^Manatus Americanus). 

 It is interesting to observe that a caput-coli is present in those of 

 the true Cetacea, as the Balcenida, which subsist on animal food of 

 the lowest organized kind. 



" Where the ilium enters the caput-coli in the Dugong it is sur- 

 rounded by a sphincter almost as thick and strong as is that at the 

 cardia. The terminai orifice is transverse and irregular. 



" The ccecum is a conical cavity, but in neither instance Tvas it so at- 

 tenuated at the extremity as in the specimen from \vhich Sir E. Home's 

 representation is taken. Its length six inches ; diameter at the base 

 or eutry of ilium four inches. The muscular coat increases rapidly 

 in thickness towards the apex, near ^hich it is one inch in thickness ; 

 its inner surface is smooth, and there is no appearance of glands in the 

 mucous membrane. This circumstance, combined with its conical 

 form, its great muscularity, and complete serous outer covering, give 

 it a great resemblance to the left ventricle of the buUock's heart. 

 Its capacity indeed is trifling as compared \vith the great development 

 of the ręst of the large intestine ; and it contains no particular 

 glandular structure ; the chief peculiarity of this ccecum is the 

 strength of its muscular tunic, and it might, without the simile 

 being far-fetched, be termed, in the Dugong, the heart of the large 

 intestines, since here its principai function is evidently to give a first 

 po-werful impulse to the motion of the long column of matter con- 

 tained in the large intestines. There is no trace of a constriction 

 at the commencement of the colon above the ilio-csecal orifice ; but 

 the great intestine is continued for a little way of equal dimensions 

 ■vvith the base of the ccecum, and then soon diminishes to a diameter 

 of one inch and a half, \vhich continues to near the termination of 

 the canal, ■vvhich becomes again wider to the antis. The parietės of 

 the large intestines are thinner than those of the small ; the muscular 

 coat consists of a thin layer of longitudinal, and a thicker layer of 

 circular fibres ; the mucous membrane is generally smooth. 



" Towards their termination the leirge intestines again become 



