20 



W. P. PYCRAFT. 



uno-ual phalanx, while Digit ITI. is slightly shortened and terminates in a point. The 

 humerus in the adult, like the rest of the wing, has undergone great flattening, as well 

 as marked changes in its extremities. Its distal end has become twisted on itself, so 

 that the radial and ulnar condyles lie one above the other, instead of side by side, and, 

 further, have become reduced so as to form confluent facets, while the olecranon process 

 is now produced backwards into a prominent, triangular spur, bearing two deep 

 grooves for the lodgment of sesamoids of large size. The proximal end has also under- 

 gone considerable chang-es, the most marked of which are the increased size of the 

 glenoid surface of the head and the great size of the fossa trochanterica. The skeleton 

 of this limb is non-pneumatic. The result of these modifications has been to permit 

 the several segments of the wing to be extended so as to form a straight- jointed rod, 

 l)ut one allowing of but little motion between the joints. In the normal wing the hand 



can be straightened out upon 

 the forearm, but the latter is 

 always, from the nature of its 

 articulations, bent upon the 

 humerus. But then, of course, in 

 the one case the wing is used as 

 a paddle, in the other for the 

 purposes of flight, though the 

 paddle of to-day, there can be no 

 doubt,was earlier used as a wing. 



Tlie Tarsal and Metatarsal 

 Bones. 



FIG. 6. — THE DUODENAL LOOP OP A KESTLING EMPEEOE PENGUIN. 



In the embryo of the 

 Emperor Penguin, to which the 

 wing just described belonged, the tarsus is wholly cartilaginous, l)ut the proximal row, 

 though showing no separate elements, is yet free and is applied in the form of a 

 cartilaginous pad to the bones of the metatarsals II.-IV. The metatarsals are also all 

 free, and, it is important to remark, have the form of perfectly cylindrical shafts, thus 

 showing that the peculiarly broad and semi-distinct metatarsals of the adult have not 

 assumed this shape by a secondary flattening process, as some have suggested, but 

 that the tarso-metatarsus, on the contrary, actually presents a primitive stage. 



VII. — The Intestinal Tract. 



Dr. p. Chalmers Mitchell (12) has described and figured the intestinal tract of 

 Catarrhactes, Spheniscus demersus, and Aptenodyfes patagonica, his preparations being 

 made from adult specimens. I am enabled here to add descriptions of this tract in the 

 Emperor Penguin, A. forsteri, and the Adelie Penguin, Pygoscelis adelise, but unfortu- 



