20 SOLENODON PARADOXUS. 
of the expanded cartilaginous end of the xiphisternum. The fibers converge as 
they pass obliquely forward to the insertion, 16 mm. in length, along the antero- 
median edge of the middle third of the humerus. The clavicular portion of this 
muscle (Plate 5, fig. 4, c) originates from the ecto-posterior border of the clavicle 
and is more or less confluent distally with the main mass of the ectopectoralis, 
though practically distinct to the common inserticn. 
The entopectoralis (Plate 5, fig. 4, f) arises just underneath the ectopectoralis, 
from the antero-ventral margin of the second rib, posteriorly to the base of the 
last sternal rib as a thin flat sheet, that becomes thicker as its fibers converge 
anteriorly to a tendinous insertion 4 mm. long at the head of the humerus, on its 
median face, just ental to the bicipital groove. At about the insertion of the 
fifth rib, there is a slight division of this muscular sheet so that its origin may be 
said to consist of an anterior and a posterior portion. These two parts evidently 
correspond to the two divisions described in Centetes by Dobson, although in 
that genus they are somewhat more extensive and distinct. 
The subclavius (Plate 5, fig. 4, d) is a very narrow band of muscle arising 
from a tendon on the anterior side of the first rib, at about 2 mm. dorsal to the 
sternum. It passes antero-dorsally to a tendinous insertion on the ental aspect 
of the clavicle just proximal to its articulation with the acromion. This muscle 
is about 30 mm. long and 2 mm. or less in width. In Centetes, according to 
Dobson, it is not present, but in Gymnura is developed about as in Solenodon. 
About 3 mm. dorsal to the origin of subscapularis, is the large tendinous 
insertion of scalenus secundus or anticus. It arises from the transverse processes 
of all the cervical vertebrae except the atlas, by tendinous and muscular fibers. 
Scalenus primus arises dorsally to the last, from the transverse processes of 
the 3d, 4th, and 5th cervicals and is inserted on the thorax as far back as the 
fourth rib, in close juxtaposition to the ventral border of serratus magnus. 
The brachial plexus takes exit between the two scaleni. 
The scalenus muscles appear thus to be much like those of Centetes and 
Potamogale, and differ from those of Gymnura and Erinaceus in that the anticus 
is present, whereas in the last two, according to Dobson, it is absent. 
