Karl Pearson and Adelaide G. Davin 
379 
our Plate XXXV, Fig. 90. We are dealing in all these cases with something much 
more closely allied to fibula than to femur. 
Again : 
The popliteus in the Womhat and Sarcuphilus i.s very large but thin, arising from the upper 
third of the back of the fibula, and inserted into the lower two-thirds of the back of the tibia. 
A few fibres of this muscle in Sarcophilus are attached to the sesamoid bone in the outer head 
of gastrocnemius. This muscle is smaller in the Giant Kangaroo, but in this and Macropiis 
honnettii its origin is purely sesamoid*. 
These two passages taken together suggest that both in the Great Kangaroo 
and the Wallaby gastrocnemius externus and popliteus arise from a fabella or sesa- 
moid at the back of the external condyle. They do not suggest that they arise from 
a parafibular sti'ucture, which may be opposed rather laterally than posteriorly to 
the femur (see our Plate XXXIV, Figs. 89 a and 89 h), and which is itself united 
by a stout band to the femur above the external condyle, this band corresponding 
in the placeritals to the tendon of gastrocnemius externus. 
Macalister's statements about other muscles are clear. He tells us that 
gastrocnemius internus arises from the internal condyle and joins the tendo Achilles. . . 
it is larger than the externus in the Wombat, but smaller in the Tasmanian Devil 
and in all species examined was without sesamoid. 
Soleus has a fibular small origin in the Wombat, but as usual has no tibial 
heads. The salens is fibular also in Tasmanian Devil, Opossum, Phalanger and 
Giant Kangaroo. 
The plantaris in the Opossum and Pei-ameles is small but separate from the 
outer condyle to the outer side of the head, but no plantaris exists in the Wombat. 
A distinct small muscle in the Tasmanian Devil passes from the back of the 
external lateral ligament and from the head of the fibula down the internal side of 
the calcaneum and into the plantar fascial. 
In a Macropus sp. examined by one of the present writers the pai-afibular struc- 
ture consisted proximally of an orthosesamoid from which gastrocnemius externus 
arose, this sesamoid articulated on a hemisesamoid which was linked by a tendon to 
the lateral face of the external condyle and from which popliteus arose ; this hemi- 
sesamoid rested on the capitulum fibulae. Plantaris was not identifiable in our 
specimen. The orthosesamoidal part of this parafibular structure is what is termed 
by most writers the gastrocnemial lateral fabella, and the hemisesamoid is what we 
term the cyamella portion of the parafibular structure. Popliteus is not attached to 
the orthosesamoidal part of the structure at all. Interpreted in our own terms we 
see that this practically agrees, except with regard to plantaris, with what Windle 
and Parsons report of Macropus rufus\: 
* Loc. cit. p. 17 of our offprint. 
+ Macalister, loc. cit. p. 19 of our offprint. 
X Journal of Anatomy and Plii/siologtj , Vol. xxxii. p. 123, 1897. They say of |j?aH(«r;.<, that the 
upper cornu of gastrocnemial /Whs-Z/rt as well as external condyle give rise to plantari.'t which is tlius a 
double-headed muscle. 
