REPORT ON THE SPHENISCID^. 



47 



phalanges. The third toe is the longest, the fourth is longer than the second, and 

 the first resembles that of the majority of swimming birds in being rudimental. The 

 first phalanx of the first toe is extremely short, but exceeds in length that of its 

 metatarsal bone. In the other toes, the first or basal phalanx and the penultimate 

 phalanx are of equal length. The other phalanges are somewhat shorter. The phalanges 

 diminish in thickness from base to apex of the toe. The basal or proximal end of each 

 presents a double cup-shaped cavity for articulation with the distal extremity of a meta- 

 tarsal bone or neighbouring phalanx as the case may be. Their distal extremities, on 

 the other hand, present two condyloid eminences separated by a vertical groove. The 

 lower surfaces of the phalanges are flattened, while their dorsal surfaces are almost 

 cylindrical. The terminal phalanx of each toe is laterally compressed and adapted to 

 the basal concavity of the nail. 



The following are the measurements of the toes of different species in inches : — 



COMPAKATIVE ReMAEKS. 



The bones of the leg in the Penguins difier as a whole but little from those of the 

 birds which most closely resemble them, except in the form of the patella, and in that 

 of the tarso-metatarsus. In respect of form and size the patella resembles to some extent 

 that of the Grebes and Divers, but differs with regard to the great development of the 

 groove for the reception of the tendon of the " ambiens " muscle. It is in the form of the 

 metatarsus that we find the most characteristic feature in the osteology of the limb of the 

 Penguins. The strongly-pronounced separation, even in the adult, of the three greater 

 metatarsal bones is, so far as I am aware, quite peculiar to the group of Spheniscidje. 



