ON THE DIGESTIVE ORGANS, AND THEIR APPENDAGES. 141 



Ccum of Oraug. 



Balaenopterus, and also in the genus 

 Delphinorhynchus, there is a small 

 caecum. 



In Man the caecum is tolerably 

 large and globular, with a long ver- 

 miform appendix, found only in the 

 human species, in the Chimpanzee, 

 the Orang, the Gibbons (in the last 

 very short), and in that marsupial 

 animal, the Wombat. In all the Si- 

 miae there is a well-developed caecum, 

 and also in the Lemurs. Fig. 138 

 represents the caecum of the Orang, 

 with a portion removed, so as to 

 shew the interior : a, the caecum ; b, 

 the vermiform appendage, seen hol- 

 low at its cut apex ; c, the entrance of the small intestines. 



In the Ruminantia the intestinal canal is of great length, and the 

 139 caecum is long, smooth, and ample, terminating in a 



blunt apex. 



In the Pachydermata the caecum is generally 

 large and sacculated : in the Horse it is constricted, 

 by three bands of longitudinal fibres, into numerous 

 sacculi. In the Hyrax there is a triple caecal ap- 

 pendage (fig. 139) ; namely, a first, or true, caecum, 

 a, contracted into folds by three longitudinal 

 bands, and so made trifid at its extremity ; then, 

 at about the distance of two feet from this, the 

 colon, 5, opens into two conical caeca, c, c, having a 

 wide base, and narrowing to a vermiform termi- 

 nation. " In looking through the vertebrata," says 

 Professor Owen, " for an analogous formation of 

 the intestinal canal, we shall find the Hyrax stand- 

 ing almost alone in this respect. Among the Mam- 

 malia it is only in a few of the edentate species 

 that the double caecum is to be met with, as in 

 Myrmecophaga didactyla, Linn., and Dasypus sex- 

 cinctus, Linn., whilst in birds, although the double 

 caecum more generally prevails, yet an additional 

 single caecum, anterior to these, has only been found 

 in a few species." 

 In the Wombat there is a short, wide caecum, with a cylindrical ver- 

 miform process ; the colon is puckered into large sacculi, by two longi- 



Triple caecum of Hyrax. 



