1882.] ANATOMY OF ERETHIZON DORSATUS. 279 
central is larger than the left lateral ; and that the Spigelian lobe is 
larger both relatively and absolutely, and is also distinctly notched ; 
and that the caudate lobe is larger and more slender. How far 
these may be individual peculiarities I am of course unable to say. 
The spleen was very different in form from that of Hystrix 
javanica. In the latter it is much elongated, while in Hrethizon it 
is oval in shape and somewhat flattened. Its length is 3/3, its 
breadth 2", 
The lungs consist of three lobes on the right side and two on the 
left, whereof the upper left lobe is divided by two deep notches. 
Fig. 8. 
/ “if 
The brachial plexus of Erethizon dorsatus. 
I-VI, cervical vertebrx ; 1, 2, 3, 4, the first four ribs; cir, circumflex nerve ; 
Ee. cut, external cutaneous ; Zn.c, internal cutaneous; M, median, Msp, 
musculo-spiral ; U7, ulnar. 
The heart is very rounded at its apex. 
The aorta gives off a large innominate artery, from which the 
right subclavian and the two common carotids arise. The left sub- 
clavian is given off separately. 
