Recerithj jyublished Ornithological Works. 113 



of either the genus Eudyptes or Spheniscus. In all essential 

 points of their anatomy, moreover, these two birds differ 

 similarly from that of the members of other genera." 



From a second important disquisition, on " the origin of 

 the Penguins,'^ we extract the following remarks : — 



" So far as the metatarsal bones are concerned, it appears, 

 from the observations of Gegenbaur, that even in those birds 

 in which the metatarsal bones ultimately fuse to form a single 

 undivided mass, these bones originally present the form of 

 four distinct and separate elements. It seems therefore, if 

 conclusions based upon embryology are of any value, that 

 we must conclude that birds, as we now know them, were 

 derived from an ancestral group, the members of which, 

 along with other peculiarities, were possessed of at least four 

 distinct and separable metatarsal bones. These four bones 

 were originally separate and distinct, but subsequently be- 

 came more or less completely fused together to form the 

 single metatarsal bone which is characteristic of the majority 

 of birds. Inasmuch as the Penguins retain the individuality 

 of the separate metatarsal bones to a greater extent than 

 other birds, it would appear that they are the modern repre- 

 sentatives of a group which had diverged from the primitive 

 avian stem at a time when as yet the metatarsal bones had 

 neither lost their individuality nor had become fused toge- 

 ther to form the single bone, which is one of the charac- 

 teristics of the majority of birds of the present day. 



" This conclusion can only be denied on the supposition 

 that the earliest members of the group of the Spheniscida 

 were derivatives from the avian stem at a period when the 

 separate metatarsal bones had been already fused to form a 

 single mass, as in modern birds, a supposition which appears 

 to the last degree improbable, when we consider that, in 

 accepting it, we must suppose that the avian metatarsal 

 bones must, in the first instance, have undergone coalescence, 

 and thereafter became differentiated from one another in the 

 members of one particular group, and in one only. It would 

 therefore appear that the group Spheniscidse is one of con- 

 siderable antiquity, and that it must have diverged from the 



8ER. v. VOL. II. I 



