ARTERIES OF 



A closer resemblance to 

 the plexiform limb-arteries 

 of the Sloths is shown by 

 the Slow Lemurs, as exem- 

 plified in the arm of Stenops 

 tardigradus in fig. 423, c. ] 



Cuvier first indicated the 

 analogous division into nu- 

 merous branches of the 

 brachial artery of the Por- 

 poise; 2 the plexuses after- 

 wards receiving a more 

 detailed account, with a 

 figure, from V. Baer, 3 who 

 also found a similar ar- 

 rangement in the pectoral 

 fin of the Manatee, 4 and, 

 with a minor degree of 

 subdivision, in that of the 

 \Talrus. 5 Y. Baer associ- 

 ates the speedy subdivision 

 of the. main artery with the 

 restricted degree of move- 

 ment of fin-shaped fore- 

 limbs : but the extent and 

 freedom of motion of the 

 long prehensile limbs of the 

 Sloths and Lemurs point to 

 other conditions. 



The extreme decree of 



o 



plexiform multiplication of 

 the arterial system in the 

 intercostal and other ver- 

 tebral branches, in the Ce- 

 tacea, more plainly relates 



1 Vrolik remarks of these plex- 

 uses, 'they consist not only of ar- 

 teries, but also of veins ; and that, by 

 dividing in branches, these ramifi- 

 cations become smaller and smaller, 

 and composed of a less number of 

 vessels.' LXIX*. p. 219. 



2 xii. (1805, torn. 4). 



3 cxcvi". fig. i. 



4 Ib. fig. ii. 



5 Ib. fig. in. 



VOL. 111. 



MAMMALIA. 



423 



545 



Plexiform branches of bracliial artery; Stenops tardigradus- 

 X X 



