26 Kl NAR LÖNNBERG, ANATOMICAL NOTES ON EAST AFRICAN MAMMALS. 



caecum (Pl. 2, Fig. 2), and the walls of this pocket are partly attaclied to the ter- 

 minal piece of the ileum on its mesial side. The opening of the ileum is directed 

 obliquely against the colon, but the passage from the caecum to the colon is very 

 effectively occluded by not less than three constrictions which each of them only 

 leave a narrow opening (Pl. 2, Fig. 2). Between these three constrictions the lumen 

 widens verv considerably so that wide pockets are formed between the narrow pas- 

 sages. At the latter the mucosa is laid in longitudinal folds by which the lumen is 

 still better closed. These pockets and constrictions correspond to colic haustra which 

 have become more strongly developed and specialised. The colon forms a spiral the 

 coils of which are quite closely connected and pressed to each other (Pl. 2, Fig. 1) 

 but which in consequence of the large size of its constituents is very big. From the 

 csecal tract the colon runs forwards on the left side below the kidney to behind the 

 ventricle. From there it returns backwards on the right side and becomes visible on 

 the (ventral) surface of the spiral near the caecal tract whcn the first coil is nearly 

 complete. In the second coil the forward ascending lim b also soon disappears below 

 other coils 1 and the only superficially visible portion of this coil as well, is behind, 

 just before the second round is completed. The third and last centripetal coil has 

 an altogether superficial situation. The same is the case with the first and second 

 centrifugal coils (the latter is the most peripheric) but the forward on the right side 

 ascending lim b of the third centrifugal coil disappears below the surface and com- 

 pletes its turn with rapidly diminished diameter. A fourth and a fifth centrifugal 

 coils with still smaller diameter encirele the root of the mesentery before the large 

 intestine runs backwards as rectum. From this description and the figure communi- 

 cated (Pl. 2, Fig. 1) it may be seen that the colic spiral of the Warthog is flatter 

 and wider than that of Sus and it may be regarded as enlarged and more specialised 

 which also is born out by its strueture in details. 2 



The colon of this young Warthog is very strongly sacculated, and the folds 

 between the hauslra very of ten cut off the greater part of the lumen of the organ. 

 This sacculation is well developed on all the centripetal coils, and also on the three 

 and a half first centrifugal coils. In consequence of this arrangement the contents 

 of the large intestine can be retarded i ti their passage through the organ and retained 

 as long lime as is necessary for the digestive process. 



The dentition of the Warthog is more specialised than in anv other mem ber of 

 the laniilv Suidce and adapted to grind coarse vegetable tnatter. The development 

 of the colon as described above is evidently also an adaptation to the same kind of 

 a diet. As the stomaoh is comparatively small it is probably of oomparatively Less 

 importance for fche digestion. The small intestine is wide to faoilitate the passage of 

 the coarse food-material, hut it is not espeoially elongated. It is thus chief ly entrusted 

 to the colic portion of the intestine to prepare the food in such a way that its di- 



1 ii een from the ventral Burface. 



: ' l Ii. iM' regarded the point where the star-mark i^ Been in the Fig. i (Pl. -> as the tärning poinl of 

 the spiral, but it i quite a matter of taste in remove 1 1 1 i -. point half a turn further upward in the figure. Ac- 

 cording t" the Bitnation >>\ the coila the tärning point appeared, however, to lic at the piace mentioned. 



