92 SLOW LEMUR. 



these vessels are also finally distributed as in 

 the upper extremity; the cylinders wholly upon 

 the muscles, and the arborescent branches on all 

 the other parts. The carotid arteries do not di- 

 vide into equal-sized cylinders, but are distributed 

 as in the generality of animals. 



" It would be of some importance in physiology 

 to ascertain whether the other slow-moving Quad- 

 rupeds have any peculiar arrangement of the ar- 

 teries of their limbs. This solitary fact is hardly 

 sufficient for the foundation of any theoretical 

 explanation of the slow movement of these mus- 

 cles : if, however, it should be corroborated by 

 similar circumstances in other animals, a new 

 light may be thrown upon muscular motion by 

 tracing a connection between the kind of action 

 produced in a muscle, and the condition of its 

 vascularity or supply of blood." 

 Fig. I. The arm and shoulder of the lemur tardigradus. 



a. The subclavian artery, lying upon the subsca- 

 pularis muscle. 



b. The division of the artery into equal-sized cy- 

 linders. 



c. The ulnar artery proceeding to divide in the 

 ufual manner. 



Fig. 2. The trunk, from below the diaphragm, of the le- 

 mur tardigradus, one of the limbs being left un- 

 finished, as it appeared unnecessary to reprefent 

 them both. 



a. The diaphragm. 



b. The descending aorta. 



c. c. The iliac arteries. 



d. The trunk of the inguinal artery, situated among 

 the cylinders. 



e. The femoral artery under similar circumstances. 



