1892.] MUSCULAR ANATOMY OF AULACODUS. 525 



SO, too, is the Semi-membranosus in having two distinct parts ; there 

 is, however, too little known at present about the musculature of the 

 Rodentia to allow of any detailed comparisons of Aulacodus with 

 other types. I content myself therefore with pointing out the 

 above-mentioned differences from its near ally Gapromys. 



II. Visceral Anatomy. 



As I have already mentioned, Prof. Garrod has described the 

 main points in the visceral anatomy of this Rodent ; I may, however, 

 call attention to a few matters which he did not specially dwell 

 upon. 



The accompanying drawing (fig. 1) illustrates the ridges upon 



Palate of Aulacodus, to illustrate the ridges upon the hard palate. 



\\i& hard palate ; these ridges, as will be seen from the figure, are 

 symmetrical, and at the same time few in number ; they are for 

 the most part in front of the molars. An inspection of the figure 

 will save the necessity for any further description. 



The Spleen is of a triangular form ; its longest diameter measures 

 2\ inches, the shorter diameter 1| inches. The Ccecum has been 

 very fully treated of by Garrod ; but he was in error, as I have 

 already pointed out in a previous paper, in ascribing a unique 

 character to the structure of this part of the alimentary canal ; in 

 Dolichotis there are a series of folds in the interior of the caecum 

 which bear not a little resemblance to those of Aulacodus. Garrod 

 has also said nothing about the folds of mesentery which support 

 the caecum ; near to the caecum the small intestine has a mesentery 



Prog. Zool. Soc— 1892, No. XXXVJ. 36 



