166 EVOLUTION AND DISEASE. 
arranged in two rows, extending along the ventral 
aspect of the trunk in both sexes ; and in situation they 
correspond to the course of the deep and_ superior 
epigastric arteries, an extraordinary anastomosis effect- 
Fic. 88.—Lemur macaco and young. (After Sclater.) 
ing a free communication between the subclavian 
arteries at the anterior part of the thorax and the iliac 
_- system of arteries at the groin, This vascular arrange- 
| ment is peculiar to mammals, and has direct relation 
| with the mammary glands. 
