REPORT ON THE SPHENISCID.E. 13 



bony spines which aflFord attachment to the tendons of the longi colli muscles in con- 

 nection with the eleventh, twelfth, and thirteenth vertebrte are developed to a greater 

 extent than in any other species. In Pygosceles and Spheniscus minor, on the other hand, 

 these spines are entirely wanting in the twelfth and thirteenth cervical vertebrae. In 

 Pygosceles I found the foramen in the transverse process of the thirteenth cervical 

 vertebra incomplete on both sides, in consequence of the want of development of the 

 anterior bars of its transverse processes. It is possible, however, that this may have been 

 an individual peculiarity. 



The articular processes present the usual arrangement. The posterior articular processes 

 of the cervical vertebrae are provided with small bony tubercles which afford attachment 

 to certain of the cervical muscles. These tubercles, in the case of the second, third, fourth, 

 and fifth cervical vertebrae are largely developed, and form well-marked bony spines 

 which diminish in size from before backwards. In the vertebras behind the fifth they 

 are scarcely recognisable until the tenth is reached, in which, as well as in the eleventh 

 they form mere nodules. The twelfth and thirteenth cervical vertebrae are destitute of 

 any trace of these nodules. 



Spinous processes are absent in the case of all the cervical vertebrae, with the 

 exceptions of the second, third, fourth, fifth, twelfth, and thirteenth. The spines of the 

 second, third, and fourth vertebrae are well-marked, pointed processes which diminish in 

 size from the second to the fourth. Those of the fifth and twelfth are mere nodules, 

 while that of the thirteenth vertebra differs from all the others in the cervical region, 

 inasmuch as it presents the form of a well-marked bony plate which is quadrilateral in 

 form and closely resembles the spines of the dorsal vertebrae. 



The following variations in respect of the spinous processes of the cervical vertebrae 

 occur in different species. In Eudyptes chrysocome from the Falkland Islands the spinous 

 process of the fifth vertebra is of large size. In Spheniscus demersus, Spheniscus 

 magellanicus, Spheniscus mendicidus, and Pygosceles the fifth and sixth vertebrae have 

 well-developed spines. In Spheniscus minor, Pygosceles, and Aptenodytes the quadri- 

 lateral spinous process of the thirteenth cervical vertebra is, relatively to the corres- 

 ponding spines in the dorsal region, of smaller size than in Eudyptes and in the other 

 species of Spheniscus. 



Comparative Remarks. — The gi*eat peculiarity of the cervical portion of the vertebral 

 column, as a whole, of the Penguins lies in the extraordinary development of its antero- 

 posterior curvatures. These curvatures are two in number. The lower half of the cervical 

 region in the natural condition of the parts describes a curve, the convexity of which is 

 directed forwards, while the upper half forms a curve, the convexity of which is directed 

 backwards. These curvatures are present in all birds, but in none are they developed to 

 the same extent as in the Penguins. So great is the convexity of the lower curve in these 

 birds that the bodies of the cervical vertebra actually come into contact with, and fill up 

 the angle formed by the two limbs of the clavicle, and consequently both the trachea and 



