222 THE VOYAGE OF H.M.S. CHALLENGER. 



fellows in certain important particulars, at the same time tliat tlioy differ from the 

 members of every other genus. 



The various species of Penguins which I have had an opportunity of examining have 

 been arranged by ornithologists, relying on the consideration of skins and feathers, into five 

 genera, namely —Aptenoclytes, Pygosceles, Spheniscus, JEudyptes, and Eudyptila. Such 

 are the genera to be found in Gray's hand-list of the genera and species of birds, and, with 

 the exception oi Eudyptila, in Sclater's Eeport on the Birds collected by the Challenger.* 

 The examination of the complete anatomj^ of these birds appears to me, so far as the 

 species examined are concerned, to lead to the conclusion that they ought all to be 

 included within the limits of three genera,^ to wit, — Aptenodyptes, Spheniscus, and 

 Eudyptes. 



In accordance with this view, the genus Aptenodytes would include the two species 

 loiigirostris and tceniatus. The anatomy of these two birds, although presenting specific 

 differences, does not, as it seems to me, justify their separation as types of tivo distinct 

 genera, seeing that in every anatomical point which can be considered of generic value 

 Pygosceles and Aptenodytes entirely agree. This much may certainly be said without 

 fear of contradiction, that in respect of their anatomy Pygosceles and Aptenodytes differ 

 less from one another than do undoubtedly distinct species 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. 



The distinctive features of the genus Aptenodytes are to be found in the large size of 

 the birds composing it, forming as they do the largest members of the entire group of 

 Spheniscidse ; in the greatly elongated form and the corresponding slenderness of the 

 bones which enter into the formation of the upper and lower jaws ; in the persistence 

 throughout life of the inter-maxillary suture ; in the elongation of the anterior narial 

 apertures, and the relation which these bear to the lachrymo-nasal fossae ; in the narrow- 

 ness of the supra-orbital grooves ; in the small development of the transverse temporal 

 crest ; in the small size and vertical direction of the post-orbital processes ; in the large 

 size of the scapula ; in the absence of a complete coracoidal foramen for the transmission 

 of the nerve to the middle pectoral muscle ; in the elongated form of the pelvis ; in the 

 parallelism of the conjoined metatarsal bones ; in the elongation and papillate structure 

 of the tongue and palate ; in the form of the proventricular gland, which may present 

 the form either of a triangular patch as in Aptenodytes longirostris , or of a complete belt 

 as in Aptenodytes tceniatus; in the length of the small intestine, which varies from six 



' Challenger Reports, Zoology, vol. ii. 



- Since wi-iting the above, I have been able to consult Cone's paper on " Material for a Monograph of the 

 Spheniscidae," in Proc. Acad. Nat. Science Philad., 1872, p. 184, and am pleased to observe that, relying on an 

 examination of the skulls of different species of Spheniscidae, that author had previously arrived at the same conclusion as 

 I have with regard to the subdivision of the group into three genera. In this conclusion we are supported by the high 

 authority of Professor Huxley, in his Essay on the Classification of Birds, Proc. Zool. Soc, 1867, p. 458. 



