1882. ] ANATOMY OF ERETHIZON DORSATUS. 281 
half of the deltoid crest of the humerus, being much connected with 
the adjacent part of the deltoid, and a portion running on to fuse 
with the brachialis anticus. 
The sternocleido-mastoid, arising as usual, is inserted into the 
antero-posteriorly extending ridge just behind the opening of the 
external auditory meatus. 
The levator clavicule arises, by a strong tendon, from the hypa- 
pophysial tubercle on the middle of the ventral surface of the atlas. 
Fig. 9. 
The lumbo-sacral plexus of Hrethizon dorsatus. 
Ant. er, anterior crural nerve; G. Sc., great sciatic nerve; JZ, last lumbar 
vertebra; Z. Sc, small sciatic nerve; O00, obturator nerve; P, pelvis; 
S$}, first sacral vertebra. 
Expanding in a fan-shaped manner, it is inserted into fascia in- 
vesting the acromion and the greater tuberosity of the humerus, 
its fibres mingling with those of the dorsal part of the panniculus 
carnosus. 
The Jatissimus dorsi sends on a dorso-epitrochlear to the ole- 
cranon. 
Proc. Zoo. Soc.—1882, No. XIX. 19 
