52 THE ANATOMV OF IIYLA C.KRULEA WHITK. 



for all the vertel)!* aie proccelous in the Hylidoe, Bufonidce 

 and CystigiiathidcB oxamiiied by him. He made observa- 

 tions on eighteen species of Hylidoe, including two specimens 

 of Hyla cop.rulea. We support his statements in regard 

 to this form. We found that in fourteen disarticulated 

 ■eighth vertebrae the centra of them all were procoelous. 



Ninth or sacral vertebra (Figs. 8 and S)). The transverse 

 processes are large and dilated, edged with cartilage. The 

 anterior zygapoph\'ses are Avell developed, but the posterior 

 are absent. In the disarticulated specimens examined by 

 us niimbering sixteen, all the centra were procoelous, and 

 thus we confirm NichoUs' work with reference to the sacral 

 or ninth of Hyla ccerulea. Immediately behind the double 

 convexity of the posterior surface of the centrum, is a 

 depression on its ventral aspect. The anterior notches 

 in the pedicles are better developed than the posterior. 

 Usually the latter, in the other vertebrse, are the more 

 prominent. The neural spine is continiious posteriorly 

 with a ridge, on each side, running towards the outer edge 

 of a transverse process, in the region of the posterior border. 



Urostyle (Fig. 10. A, B.) The urostyle is somewhat 

 under half the total length of the vertebral column. It 

 consists of a ventral cylindrical portion and a dorsal crest. 

 The former is straight, but curves sUghtly ventrally in the 

 anterior region. The articular surface is on the anterior 

 face of the cylindrical part of the urostyle. It is oval, 

 and bears the double concavity into which fits the double 

 •convexity of the sacral vertebra. The sides of the anterior 

 face are concave. Anteriorly, the crest is more or less 

 perpendicular, while the dorsal edge slopes away gradually. 

 The anterior edge is about equal in height to the minor 

 axis of the articular surface. The crest runs from the 

 anterior end to about two-thirds of the length of the 

 ossified portion of the urostyle. Posteriorly, the latter 

 is tipped with cartilage. Apparently, the neural canal's 

 nmning obliquely upwards and opening on the dorsal 

 surface of the neural crest, is a normal feature. Seventeen 

 ■complete specimens of urostyles were examined. The 

 neural canal was present in them all. A hair or l)ristle 

 passed through fifteen, from the anterior opening of the 

 canal to the exterior on the dorsal surface. In one 



