23 
Macalister also describes separately a retro-clavicularis included by 
Hyrtl as part of the subclavius, and passing from first rib to acromion 
and supraspinous fascia. 
In Orycteropus* Galton found the subclavius arising from the manu- 
brium sterni and its junction with the first rib, and also by fibres pro- 
longed from the terminal aponeurosis of the rectus abdominis. 
Humphry} in the same animal found it arising from first and second 
costal cartilages and adjacent part of sternum, while both authors 
fonnd it inserted into acromial part of clavicle, acromion, and fascia 
over the supraspinatus muscle; while in addition Galton found it in- 
serted into a sesamoid bone just below the acromio-clavicular joint, 
embedded in fibres of the deltoid, and which he surmises may possibly 
be a “meso-scapular segment.’’ He also says that a thin stratum 
derived from the lower portion of the muscle finds insertion by 
aponeurosis along the inner edge of the strong coraco-acromial 
ligament. 
According to Humphry{ and Macalister the muscle is entirely ab- 
sent in Manis and the Anteaters and Armadilloes. In Ai it was thin 
and weak. In Tutusia$ Macalister found it very large. 
In Dasypus sexcinctus, according to Galton|| and Macalister, the 
muscle is strongly developed. And in Cuvier & Laurillard’s plate, 
No. 260, the muscle is seen closely to resemble that in Notoryctes. 
Galton describes it as arising from the “ irregularly oval and roughish 
depression seen at the expanded anterior termination of the first rib, 
and also from its superior edge for a short distance.” “It is inserted 
by a flat tendon along the whole extent of the upper ridge of the long 
acromion process of the scapula, and becomes, moreover, continuous 
with the strong fascia which covers the head of the humerus and 
which is lost over the supra-spinatus. The strong coraco-clavicular 
ligament passes across through the substance of the muscle, close to 
the insertion of the latter, splitting it into two unequal portions, the 
smaller and anterior of which dips under the hgament to join its ten- 
don, while the largest portion passes over the ligament.” This inser- 
tion (see also Galton’s fig. 2, pl. 44) much resembles that in Notoryctes. 
In Dasyprocta cristata Mivart and Murie** describe a “ sterno-scapu- 
lar ” muscle with double origin, the smaller factor of which they sug- 
g@st (following Meckel}+) may be subclavius. (Galton{{ refers to this 
observation in connection with the subclavius in Dasypus.) The 
whole muscle is long and narrow, and the smaller head arises from the 
outer side of the base of the manubrium and from the cartilage of the 
first rib. The larger head arises from the sternum between the origins 
of the first and second parts of the pectoralis major. The muscle is 
inserted slightly into the distal end of the clavicle and into the scapula 
and fascia over the supra-spinatus. 
In the Rabbit and Guinea Pig, according to the same authors,$$ the 
two slips are present, but in the Hare there is only one broad origin. 
In the Porcupine also, according to Galton,|||| the muscle is a single 
strap-like band arising from the costal portion of the first rib, and 
*xv., page 571. + xxi., page 297, and xxxv., page, 494. {xxii., page 
26. §xxvil., page 241. ||xiv,, page 528. [ xxvii, page 241. **xl., 
page 398. TfxxXviil., page 444. {{ xiv., page 528.  §§ xL, page 398. 
| xiv., page 529, and vi. Pl., 229, fig. 2. 
