SHUI'KI.DT : OSTKOI.OCV Ol' I III'. 1 1 I.Ki )1 HONES. 235 



gradually increase in length and curvature. The costal ribs are also 

 much compressed from side to side, and are graduated in a similar 

 manner. 



Considering tlie I'ertehric of the cervical rci:;ioii from the first to the 

 seventeenth inclusive, we are to observe that the characters they in- 

 dividually present are for the major part quite different from those 

 found in the corresponding vertebrae in the neck of either Tantalus or 

 the Herons. The atlas has a broad and deep neural arch, with its 

 postero-external angles produced. Its articular cup is notched su- 

 periorly by the odontoid process of the axis. Below, it has a bifid 

 hcemal spine, and its other characters are (juite of the common 

 ornithic type. In the axis vertebra there is a low, thickened neural 

 spine, with a rather longer, better developed and more pointed 

 hremal one. This vertebra also has a completed lateral vertebral canal, 

 with parapophysial spines projecting from them behind. These spines 

 are longest on the third vertebra, and the fourth. On the fifth they 

 show signs of shortening, which is decidedly the case in the sixth 

 cervical, after which they rapidly shorten throughout the series as we 

 pass backwards, to become quite absent in the twelfth. There is also 

 a progressive lengthening of these vertebrae from the third to the 

 eighth inclusive, they becoming at the same time more slender in ap- 

 pearance. From the ninth backwards they gradually shorten and 

 thicken again until they finally assume the form of those of the pre- 

 dorsal ones. Semi-al)orted neural spines are found upon the third, 

 fourth, fifth and sixth cervicals, being entirely absent on the seventh, 

 and do not again appear till we come to the thirteenth where this 

 process is bifid. On the fourteenth it is represented by a single 

 median tubercle, while on the fifteenth to the seventeenth inclusive 

 it is elongated and plate-like. Lateral vertebral canals extend through- 

 out the series from the second to that vertebra which first bears free 

 riblets. In the middle of the chain, the pleur- and parajjophyses 

 closing them in are rather broad and deep. The infero-median 

 hypopophysial carotid canal commences with the fifth vertebra, where 

 it is open and rudimentary. It is nearly closed on the sixth, to be- 

 come completely so on the next following one. After this its walls 

 are unusually complete, and antero-posteriorly deep. This condition 

 obtains until we come to the twelfth cervical where we find it small 

 and o|)en again. In the thirteenth its j)lace is occupied by a single, 

 plate-like haemapophysial spine, but this latter character rajjidly aborts 



