18 
part of the muscle is costofascial in origin, is closely attached to the 
pectoralis quartus, and has the usual humeral insertion close to the 
teres major. Other Edentata vary as regards origin of the muscle, but 
all possess the usual humeral insertion, while, in addition, they all 
possess a dorso-epitrochlearis element ‘associated with the latissimus, 
and often closely connected with the panniculus or pectoralis quartus. 
The insertion of the dorso-epitrochlear muscle is more variable than 
in marsupials, and is frequently prolonged into the fascia of the fore- 
arm (Chlamydophorus* and Orycteropust ), or even to the palmar fascia 
(Cyclothurust ), and it may be partly united with the scapular triceps, | 
as in Orycteropus.§ 
In Talpa Cuvier & Laurillard|| figure the latissimus as giving off a 
slip to the fascia of the forearm before becoming inserted into the 
humerus. This is not mentioned by Freeman,{ but is plainly a true 
dorso-epitrochlear slip. 
In this animal, as noted by the latter observer, the latissimus is 
rather large, and consists of two portions, anterior and posterior, 
separated by an interspace. The two parts, however, unite, and are 
humeral in their insertion. 
A dorso-epitrochlearis is present in all the Insectiwora. It is broad 
and thin in Gymnura.** In Chrysochlorist+ it consists of fibres, which 
pass from the latissimus to the ossified tendon of the flexor profundus 
digitorum. The latissimus itself in this animal is inserted into a pro- 
cess running out from the internal condyle of the humerus. 
The dorso-epitrochlearis is usually present in Rodentia and Carnwora. 
In the Rabbit{{ it is continued into the flexor carpi ulnaris according 
,to Humphry. 
M. serratus magnus (figs. 6, 7, and 21, s.mg.) consists of two 
portions—anterior and posterior. 
The anterior, by far the larger, is a fan-shaped muscle, partly 
cervical, but chiefly costal in its origin. 
The costal fibres arise as a series of fleshy slips from the first 
five costal arches, the more posterior origins being partly over- 
lapped by the lateral free margin of the M. rectus abdominis. 
The origin from the first costal arch is from the vertebral seg- 
ment, and partly indeed from its tubercle dorsally. The cervical 
fibres form only a small anterior portion of the muscle lying 
dorsal to the cords of the brachial plexus, and arising from the 
transverse process of the seventh cervical vertebra, and slightly 
from the corresponding portion of the fused cervical vertebral 
mass. 
This anterior portion of the muscle is inserted along the whole 
length of the ventral lip of the vertebral border of the scapula 
close to the rhomboid insertion. 
The posterior sector of the muscle (not shown in drawing) is 
separated from the anterior at its origin by a very considerable 
* xxvii., page 236. {xv., page 574. txxvii., page 237. §xv., page 
574. ||vi. Pl., 80, fig. 5. xi, page 212. ** viii., page 395. TT xxv., 
page 807. ttxx., page 151. 
