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



form, as in Spheniscus demersus aud Spheniscus mendiculus, or zonular, as in Spheniscus 

 magellanicus and Spheniscus minor ; in the length of the small intestine, which varies in 

 length from seven times that of the vertebral column in Spheniscus minoi', to nineteen 

 times in Spheniscus magellanicus; in the ossification of the syringeal rings, and their 

 immobility upon one another ; in the obliquity of the pessulus with reference to the long 

 axis of the trachea ; aud in the presence of a tracheal septum which may nearly equal 

 the length of the tracliea as in Spheniscus magellanicus, or may be entirely absent 

 as in Spheniscus minor. 



If now we consider the different species of the genus Spheniscus which I have had 

 an opportunity of examining, it appears that ornithologists hold different views 

 with regard to the specific distinctness of Spheniscus magellanicus as compared 

 with Spheniscus demersus. On the one hand, Sclater ^ and others regard these two 

 as perfectly distinct species, while, on the other hand, Coues'^ is of opinion t\\a,t Spheniscus 

 magellanicus is " simply a collared variety of Spheniscus demersus." 



A careful examination of the entire anatomy of several specimens of each of these 

 birds leads me to the conclusion that the view of the last-named author is the correct one, 

 and that these two birds are simply varieties of one and the same species. The skulls of 

 both (PI. II. figs. 1-8) are in every respect similar, and the same remark holds good 

 •of every bone in the skeleton of each, with this exception, that the bones of Spheniscus 

 magellanicus are slightly larger than those of Spheniscus demersus. It is true, as 

 observed by Hyatt,'' that " Spheniscus magellanicus is much the larger bird " of the two, 

 but in view of the difference in size already noticed of different varieties of Eudyptes 

 ehrysocome, this feature of itself must be deemed of but little value in attempting to 

 decide as to the specific distinctness of different birds. More relialjle conclusions may be 

 founded on the consideration of their entii-e anatomy. With regard to this I found that 

 in two specimens of Spheniscus demersus, the proventricular gland presented the form of a 

 crescentic or triangular patch, which was limited to the left wall of the stomach. In 

 every specimen of Spheniscus magellanicus, again, which I dissected, the proventricular 

 gland presented the form of a complete belt, which completely surrounded the gastric 

 cavity. This difference would apparently justify us in concluding that these two birds 

 are specifically distinct. On the other hand, it is to be noted that in a third specimen of 

 Spheniscus demersus the proventricular gland was zonular in character, and although 

 the separate glandules composing the belt were more sparsely distributed on the right than 

 on the left wall of the stomach, yet at no point were these glandules entirely absent, as was 

 the case on the right wall of the stomach in both the other specimens which I examined. 

 In this third specimen of Spheniscus demersus, therefore, there was a manifest 



1 Challenger Reports, Zoology, part viii. p. 125. 

 '■' Proc. Acad. Nat. Sci. Philad., 1872, p. 173. 

 '^ Proc. Boston Soc. Nat. Hist., vol. xiv. p. 249. 



