CHAP. IVJ THE GENERAL ANATOMY OF THE LEMUROIDEA 91 



(c) The incisura oesophagea is very deep and of considerable 

 extent in the cranio-caudal (antero-posterior) direction. In a 

 Lemur mongoz dissected by me, it constitutes also an incisura 

 gastrica. Such a deep incisure is again a mark of the primitive 

 status of its possessor. 



The liver has also characters distinguishing it from those of 

 the higher Primates, though not necessarily primitive in them- 

 selves. Among such characters, the following are to be ranked. 



(a') An enormous incisura duodenalis on the right side, in 

 which the duodenum comes to the surface between the right 

 central and right lateral hepatic lobes. 



(6') The left lateral lobe curves forwards and extends across 

 the mid-ventral line to the right hypochondrium. 



(c') The lobus caudatus is divisible into a pars papillaris (lobus 

 Spigelii of human anatomy) and a lobus caudatus proper. Of 

 these, the papillary portion is insignificant and projects but 

 slightly beyond its surroundings. The true caudate portion is 

 on the contrary extensive. Passing downwards, it is hooked 

 round the inner aspect and lower pole of the right kidney. 



(d') The impressio renalis is consequently provided by the 

 caudate lobe and the right lateral lobe conjointly. 



The Pancreas is already much attenuated where it crosses the 

 aorta on its way towards the left kidney (cf. Patten, op. cit.). 



The large size of the duodenum is noteworthy. This part 

 of the intestine consists of a longer vertical part, and a shorter 

 transverse part, distal to the former; it crosses the vertebral 

 column at a level as far back as that of the fourth lumbar vertebra. 

 The caecum is prolonged into a tapering appendix of some size 

 (Fig. 49). 



The loop in the transverse colon has been mentioned in an 

 earlier chapter. Here it will suffice to note that the loop is 

 "sinistral" in the viscera (cf. Fig. 50) examined (i.e. from a speci- 

 men of Lemur mongoz). In Galago garnetti I find the loop is 

 dextral, as it is said to be in Propithecus diadema 1 , in which 

 the loop is far more complicated than in Lemur mongoz, and is 



1 Cf. Max Weber, Die Saugethiere, 1904; also Beddard, P. Z. S. 1908, May 26, 

 p. 578, and Mitchell, Zool. Trans, xvn. Part v. Dec. 1905 (for an account of the 

 colic loop in other mammals). 



