PENGUINS. 



57 



Fig. 2.".. — Pelvis of 

 Catarractfs tlemer- 

 sits, dorsal view. 



Splienisciila?," from which, on ;iccoiiiit of tho importance of (k'termiiiin;^ tho rchi- 

 tioiisliij) of tlio higher group of birds, we sliall quote freely in the following. 



The vertebral column is characterized by the o])isthoc(elous character of the dor- 

 sal vertebrae, a character which, judging from the frequency of its occurrence in the 

 two grou])S, is more truly reiitiliaii than avian, and by the mobility of 

 the dorsal vertebrie upon one another, and the absence, even in the 

 adult, of that complete anchylosis between the dorsal and luml)o- 

 sacral vertebnu on the one hand, and of the latter with the jielvic 

 bones on the other, which obtains in the majority of birds. The 

 opisthocoelous character of the vertebraj shows itself for the fii-st time 

 in the third dorsal ; the cervical and the two first dorsal vertobne being 

 saddle-shaped. The succeeding dor.sals differ in having the ante- 

 rior surfaces rounded and globular, while their posterior surfaces are 

 deeply concave. The luml)0-sacral portion of the vertebral column 

 never becomes anchylosed with the pelvic bones, not even in the 

 adult (Fig. 25). The pubis does not coalesce with the ischium, ex- 

 cept where it enters the acetabulum. 



The uncinate processes of the ribs are exceptionally large, and 

 are only connected with the ribs by articulations, never becoming 

 anchylosed with them as in the majority of birds. 



The shoulder-blade (Fig. 26) is remarkable for its enormous size and its great 

 width jiosteriorly, ami thecoracoid bone for its great strength. The most characteris- 

 tic feature of the wing, as a whole, is perhaps the great amount of coinpivssion exhili- 

 ited by all its bones, offering, when the wing-paddle is 

 carried forward while swimming, the minimum resist- 

 ance to the surrounding water. Furthermore, the 

 movements permissible between the different bones are 

 much more limited than in other birds — so much so 

 that flexion and extensit.n in the joints beyond the Fic.-JC.-Scapui.iof G./,,r™w«. 

 shoulder can scarcely be said to be possible. These articulations, however, .''dinit of a 

 very considerable amount of rotation, converting the wing into a screw-like blade. The 

 wings are never used as oars, but are brought into use alternately. The metacarp.al 

 consists of a single bone, which shows, however, the three elements of which it is 

 composed. The first or radial metacarpal is destitute of any phalanx, and the jiollex 

 is consequently absent; the second finger h.as two phalanges, and the third only one. 



The legs are less modified than the wings, but the tarso-metatarsus ]iri'scnts fea- 

 tures which serve at once to distinguish that bone from the corresjtonding skeletal 

 element of any other grou]) of birds, being altogether .shorter ami 

 broader than in these, with the single exception of the genus Vvegatn. 

 From l-^rc'jiidi, however, as from all other birds, the ]ienguin is dis- 

 tinguished by the clearly-defined separation of the metatai-sal elements, 

 the shafts of which are diffi-]-enti;ited from one another, while in other 

 birds these bones are indistinguishalily fused togellu'r. Of the ullicr 

 bones, only the patella is remarkable, it being very large aixl wedge- 

 shaped, with a greatly develo]>ed groove for the tendon of the ami ieiis 

 nuiscle. Four toes are .always present, the liallux being directed forward. 



It lias been suggested to me. Professor Watson further says, that the large devel- 

 opment of the cutaneous muscles in these birds is jirobably a mean-; ulunliy water 



iiieuiarBiu of 

 t'ittiimuUt, 



