NARRATIVE OF THE CRUISE. 



325 



" The lateral position of the nostrils. 1 The presence of a distinct gluteus quintus 

 muscle. The formation of the biceps humeri muscle, which gives off a patagial slip 

 from its coracoidal head. The characteristic sternum. The absence of haemapophyses 

 on the dorsal vertebrae. The pneumatic os humeri. 

 The generally pneumatic condition of the skeleton. 

 The proportion of the manus to the humerus and 

 ulna." 



The Procellariinae, which compose the rest of 

 the Procellariidae, contain the following genera : — 

 Pvocellaria, Cymochorea, Halocyptena; (Estre- 

 lata, Puffums, Adamastor, Majaqueus, Bulweria; 

 Prion; Daption, Pagodroma, Aeipetes, Thcdassceca, fm. 129. -Base of Beak of niomedmexuians, to show the 

 Fulmams, Ossifraga ; Pelecanoides. These, with *™ and position of the nostri1 -' 



the exception of Pelecanoides, form a natural group distinguished by the followino- 

 characters from the Albatrosses (Diomedeinse) :- — 



a 



Fig. 130. 



a 



m 



Fra. 131. 



Fio. 130. — Beak of Thalassixca glacicdmdes. a, the aperture of the nasal tubes, from the front. Natural size. 

 Fid. 131.— The same parts of Aeipetes anlarcticus. 



" The more or less dorsal position of the nostrils, the form of which however varies, as 

 has already been described, though they are never lateral. The absence of a gluteus 



1 This feature, in which the Albatrosses are apparently more primitive than are either the Oceanitidoeor the other 

 Procellariidce, can hardly, if my views about the relationships of these groups to each other be correct, be considered to 

 have been a character of the common Petrel-ancestor. It may be more probably explained as due to arrested develop- 

 ment during embryonic life, as a study of the development of the nostrils of other Petrels would probably show that- 

 these are actually, at some time, lateral, and subsequently coalesce. 



