400 
On the Semmoids of the Knee- Joint 
Fig. 89 a and Fig. 89 h. Photographs of anterior and lateral aspects of a moist preparation of the 
right knee-joint of Sarcophilus ursiiiua, the Tasmanian Devil, from the Museum of the Royal College of 
Surgeons, showing the parafibnlar sesamoid in what we believe to be the true position, i.e. mounted on 
the head of the fibula with a ligament connecting its summit with the lateral face of the femur above the 
external condyle. 
Plate .YA'A'I', Fig. 90. Drawing of the lateral aspect of the right knee-joint of Halmaturus sp., the 
Wallaby, to indicate the position of the parafibular sesamoid on the head of the fibula. 
Fig. 91. Drawing of the postero-lateral aspect of the left limb of Conicia zehrata to show a note- 
worthy sesamoid arrangement, d is a parafibular sesamoid united by a ligament to 6 a paratibial 
sesamoid, which might be a lunula. Drawing by Mr S. Steward. 
Plate XXXVI. Di awings of the knee-joints of Birds. Cf. Plate XXI, Figs. 46, 48, 49, and Plate XXII, 
Figs. 50, 51, 52, and 53. 
Fig. 92. Drawing of lateral aspect of left pelvic limb A of Hesperornis regalis, after Marsh. Note 
the giant patellf — longer than femur — and the condyles of the femur enclosed by patella; tibia 
and fibula. 
Fig. 93 o and Fig. 93 b give the mesial (Bj) and lateral (B2) aspects of the right and left knee-joints 
of the Cormorant; the patella is of relatively sm?ller size than that of Hesperornis regalis, but clearly 
built on the same lines ; the continuity of the ridges aa' and hh', — the pro- and ecto-cnemial ridges of the 
tibia carried right up the lateral face of the patella, — must be emphasised, as in favour of released 
cnemial crest i-ather than a co-ossified patella. 
Fig. 94. Drawing of the lateral aspect of the left pelvic limb C of Colymbus torguatus after Coues. 
There is a giant cnemial crest. A comparison of A and C suggests either that (i) the cnemial crest is a 
co-ossified patella or (ii) the patella a released cnemial ores ; independent origin of both is hard to accept. 
Bo is certainly an argument in favour of (ii). 
Plate XXXVII, Fig. 95 and Fig. 96. Drawin'^T of sections respectively of the fibular crest of a young 
and an embryo platypus. In the former case ossification is complete but the arrangement of the 
Haversian canals at the top of the plate, i.e. the proximal end of the fibular crest, seems far from 
incompatible with a separate centre of ossification. In the latter there appear signs of ossification 
starting towards the summit of the crest in an area widely removed from the centres of ossification of 
the shaft or of the fibular head. 
