220 R. W. SHUFELDT 



and standing apart by quite an interval, there are two conspicu- 

 ous articular facets, each being semiellipsoidal in form, with its 

 major axis placed transversely. To either outer side of one of 

 them, there is a bluntly rounded process, each somewhat curved 

 toward the median plane of the bone. The neural canal is 

 large, short, and cylindrical in form. The broad centrum, of 

 triangular outhne posteriorly, is but a mere thin plate, smooth, 

 and moderately concaved on its under side. Still more pos- 

 teriorly are the enormously developed postzygapophyses, divided 

 by a shallow, triangular median notch behind. Each has a 

 rounded outline, the general surface of the two above being 

 smooth and uniformly convex. Upon the inferior aspect each 

 is markedly convex from before backward, the extensive outer 

 surface of either one being smooth and articular in character. 

 All of these points are well shown in the several plates in which 

 this vertebra appears. 



Counting the axis as the second vertebra from the skull in 

 the cervical series, as shown in the plates (figs. 3, 4, and 5), 

 we next come to the one marked 10 in the figures. To this 

 vertebra I have given very careful study in all the material at 

 my hand, including typical land tortoises from various parts 

 of the world, pond turtles, the great marine forms, and the soft- 

 shelled types. 



In the land tortoises, such as Testudo and Terepene, and 

 many others wherein the carapace of the shell is entire, with 

 all of its component parts solidly coossified together, and not a 

 semblance of an hiatus among any of them, this vertebra, while 

 it presents a number of morphological characters referable to 

 the true cervical vertebra next in advance to it in the living 

 animal, must nevertheless be considered as the first dorsal 

 vertebra in such chelonians as I have thus far examined. In 

 the various species of Amyda — and especially in such forms as 

 Amyda cartilaginea — at least two-thirds of its characters pertain 

 to a cervical vertebra at the termination of the series. Its 

 centrum projects considerably beyond the postzygapophyses 

 above it (figs. 3 to 10), and each of its postero-external angles 

 presents a small, roughened surface, that in life is feebly coossi- 



