STUDIES OF THE MACROCHIEES. 



331 



blade-like portion behind is very thin, its surrounding margin 

 only being thickened to lend it tlie proper support. 



When we come to measure the lengths of the bones composing 

 the pectoral limb in this Trogon, we find that the humerus is 

 '^rl centimetres long, the ulna 3'6 ; and the skeleton of manus, 

 measuring from the summit of the carpo-metacarpus to the distal 

 Hpex of the last phalanx of index digit, 3-0 centimetres long. 



Of tlie Pelvic Limb (PI. XIX. fig. 13).— Trogons have a 

 thoroughly pneumatic femur, and a large foramen or two to 

 admit the air are found upon the anterior aspect, near the sum- 

 mit of the bone, between the trochanter and the head. I am not 

 quite certain but that the tibia also possesses a moderate amount 

 of pneumaticity, as the shaft is completely hollow and the bone 

 has the general appearance of a pneumatic one. However. I 

 have failed to discover the presence of the foramina in this part 

 of the skeleton of the leg. As for the fibula and the remaining 

 skeletal parts of this limb, they are entirely devoid of this 

 feature. 



Eeturning to our examination of the femur, it is to be noted 

 that the trochanter is but feebly pronounced, and does not rise 

 above the summit of the bone. The caput femoris is globular 

 and quite sessile with the shaft. We can scarcely discern any 

 pit whatever upon its superior surface to lodge the attachment 

 of the ligamentum teres. Descending to the shaft we find this 

 part of the bone nearly cylindrical in form, very smooth, and 

 quite straight. At its distal extremity the condyles are rather 

 small comparatively ; the external one being situated lower, and 

 at the same time somewhat more prominent than the internal 

 one. 



Trogons possess a very well-developed patella of a subcordate 

 form, it being fully twice as wide as it is deep. 



Eegarding the Jibula, we find that it presents little or nothing 

 worthy of special note. Feebleness of development charac- 

 terizes this bone in the Trogons throughout. Its head is 

 small and the shaft slender, the lower end of tlie latter being 

 free from the tibia, and descending to a point about opposite the 

 junction of the middle and lower thirds of its shaft. Scarcely 

 any evidence exists of the presence of the tubercle for the inser- 

 tion of the tendon of the biceps muscle, a feature which is 

 quite prominent in some birds. 



LINN. JOUllN. — ZOOLOGY, TOL. XX. 26 



