INTESTINAL TRACT OP MAMMALS. 513 



It is differentiated into a proximal portion continuous with the caecum, and forming 

 the ascending colon of human anatomy, and a very large and capacious colic loop 

 which forms a series of minor loops, the most distal of which may be identified with 

 the sigmoid flexure of human anatomy. Finally, there is a short rectum. 



Family Anthropomorphic. Gorilla savagei (fig. 45, p. 514), Anthropopithecus niger, 

 Simia satyrus. 



In the Gorilla (fig. 45) there is no single loop to represent a separate duodenum. 

 Meckel's tract is relatively very long and consists of a large number of irregular minor 

 loops very closely set together and forming a compact mass arranged round three- 

 quarters of the circumference of a circular outgrowth of mesentery, the last quarter 

 being occupied by the ascending colon. The caecum is short, forming an elongated 

 oval globe with a very long twisted vermiform appendix. The hind-gut is capacious 

 and its calibre is much larger than that of the fore-gut. It is differentiated into 

 three regions — a proximal portion continuous with the caecum ; a very large loop 

 displaving three rather irregular wide loops, the most distal of which may be regarded 

 as the equivalent of the sigmoid flexure ; and a relatively short, straight rectum. 

 The extensive attachment of the mesocolon to the great omentum has produced 

 complexities in the veins. The anterior mesenteric vein is enormous and curves 

 round the Meckelian mesentery, its distal end forming a loop with a factor of the 

 right colic vein ; it receives irregular branching tributaries from the minor loops of 

 Meckel's tract. A very large tributary of the anterior mesenteric corresponds to the 

 right colic vein of human anatomy and drains by various branches the distal part of 

 Meckel's tract, the caecum, and a considerable portion of the colon. The posterior 

 mesenteric vein forms a branching system draining the rectum proper and the 

 remainder of the colic region of the hind-gut. 



In the Chimpanzee the arrangement of Meckel's tract is similar to that in the 

 Gorilla. The caecum is relatively larger and more capacious, whilst the long vermi- 

 form appendix is less twisted. The hind-gut has the same general size, capacity, and 

 relations, but is less divided into definite minor loops. The general arrangement of 

 the mesenteric veins is similar. 



In the Orang there is no distinct duodenum. The minor loops of Meckel's tract 

 are arranged in a proximal and distal set, the expanse of mesentery on which they 

 are suspended being deeply divided between these two regions. The caecum and 

 vermiform appendix differ very little from those of the Gorilla, and Chimpanzee. 

 The hind-gut shows three distinct regions. There is a very wide portion forming one 

 large loop corresponding to the ascending, transverse, and descending colons of human 

 anatomy; then a very large region which may be regarded as the sigmoid flexure and 

 is composed of a number of minor loops, and finally a short straight rectum. I find 

 that I have not detailed notes on the mesenteric veins. 



