- 
oO 
group, the attempt to ascertain the homologies of its muscles to 
those of other forms may be rendered difficult through a con- 
fusion between muscular segmentation dependent upon mere 
fanctional modification of the species and that more fundamental 
segmentation into muscle-fibre-groups which, while not indepen- 
dent of function, is yet the expression of definite morphological 
type. 
In the section of work now presented I have not found this 
difficulty to offer any insuperable obstacle to a quite intelligible 
reading of the muscular arrangements in Notoryctes. In spite of 
its specialised structure, indeed, the muscular organisation of 
this animal bears very evident traces of its affinity to other more 
or less allied forms ; and although there can be no doubt that the 
marsupial type is the prevalent one, there are features, for a 
structural parallel to which one must go outside the limits of the 
Marsupralia. And I cannot avoid the conclusion that the 
structural resemblances in particular to certain members of the 
order Hdentata are not all to be explained as merely the coinci- 
dences of somewhat similar functional modifications, but are the 
enduring evidences of a real if distant morphological kinship. 
Neither in Z'alpa nor, apparently, in Chrysochloris do we find 
any such striking similarities to Votoryctes as we do, for example, 
in Chlamydophorus ; and this in spite of the fact that the habit 
of life of the first-named animals is probably much more like 
that of Votoryctes than is that of Chlamydophorus. So far as I 
can judge from my very limited acquaintance with the myology 
ot Chrysochloris, the muscles of the anterior limb of that animal 
are far less like those of Wotoryctes than at least a superficial 
comparison of the skeletons would lead one to expect. 
M. panniculus. 
The subcutaneous sheet of the panniculus carnosus on the 
ventrolateral aspect of the body consists mainly of three systems 
of fibres—(a) a platysma system ventrad of the neck and chest, 
(6) a humeral system passing transversely and obliquely outwards 
on the ventral aspect of the thorax and abdomen to the region of 
the axilla (fig. 1, p.c¢.), and (¢) a system of longitudinal and 
oblique fibres crossing backwards from amongst the other abdom- 
inal fibres to the region of the marsupium which some surround, 
whilst others enter and end in the folds of skin forming the 
margin of the opening of the pouch (sphincter marsupii). This 
system of longitudinal fibres is lost posteriorly in the region of 
the cloacal aperture and root of the tail, whilst its more lateral 
portion is continued over the front of the inguinal and femoral 
regions (abdominis femoralis). On the dorsal aspect of the 
