44 CERVICAL VERTEBRAE. [chap. i\\ 



grown (see Fig. 5, p. 20) ; that of the axis is still distinct 

 in an adult Omithorhynchas. Though in this respect they 

 present an approximation to the Sauropsida (Reptiles and 

 Birds), they differ from that group, inasmuch as there is not 

 a gradual transition from these autogenous transverse pro- 

 cesses of the neck (or cervical ribs, as they may be con- 

 sidered) into the thoracic ribs, for in the seventh vertebra 

 the costal element is much smaller than in the others, 

 indicative of a very marked separation of neck from thorax, 

 not seen in the Sauropsida 



