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



Spheniscus demersus, and by Sclater,^ who is of opinion that it is a " quite distinct " species 

 from Spheniscus demersus. In the absence of an anatomical examination it is impossible 

 to decide which view is correct, but I shall be surprised if farther research does not 

 demonstrate that Spheniscus humboldtl is simply a variety, and by no means a well- 

 defined variety, of Spheniscus demersus. It appears to me that the difference in external 

 appearance between Sj^heniscus humholdti and Spheniscus demersiis is even less than 

 that which exists between Spheniscus demersus and Spheniscus mag ellanicus, and in view 

 of the similarity of the anatomy of the two last-mentioned birds, it appears to me likely 

 that an accurate anatomical examination of Spheniscus humholdti vnU show that it is simply 

 a variety of S^^heniscus demersus, and one that differs less fi'om Sj^heniscus demersus than 

 does Spheniscus magellanicus. 



Lastly, relying on the results afibrded by a minute anatomical investigation, there 

 can be no doubt that both Spheniscus mendiculus and Spheniscus minor constitute well- 

 defined species, the specific characteristics of which are to be found in the foregoing 

 pages. 



Spheniscus minor ajjpears to be the most aberrant species of the genus, and differs 

 more from any of the other species than these do from one another in respect of the form 

 of the skull, in that of the proventricular gland, in the length of the small intestine, and 

 in the total absence of a tracheal septum. In some respects, moreover, especially in the 

 form of the skuU and in that of the conjoined metatarsal bone, Spheniscus minor seems to> 

 occupy an intermediate position between Spheniscus, as represented by Spheniscxis 

 demersus, and Eudyptes, as represented by Eudyp'tes chrysocome. Its relationship to 

 Spheniscus, however, is closer than to Eudyptes. The difference between Spheniscus 

 minor and the other species of the same genus nevertheless does not appear to me to be 

 sufiicient to justify the establishment of a distinct genus for the reception of this species, 

 as has been done by several ornithologists."^ 



Origin of the Penguins. 



It has been remarked by Owen,^ that in respect of several osteological features the 

 Penguins present exceptionally reptilian characters. These characters are to be found 

 more especially in the opisthoccelous character of the dorsal vertebrae, and in the form of 

 the metatarsal bones which present an amount of differentiation from one another which, 

 so far as I am aware, is met with in no other group of birds. 



The reptilian arrangement of certain of the muscles of the Penguins has, moreover, 

 been referred to by Gervais and Alix.* 



1 Challenger Reports, Zoologj', part viii. p. 126. 



- Gray, Hand-list of Birds ; Gould, Birds of Australia, vii. pi. Isxxv. ; Bonaparte, Coujptes rendus, 1856, torn. 

 xliii. p. 646. 



^ Cyclopaedia of Anatomy, Art. "Aves," vol. i. p. 270. 

 * Ostdologie et Myologie des Mancliots. 



