O. HTDKASPIS. 



221 



Fig. 60. 



Shell of Hydraspk hilarii. 



Synopsis of the Species. 

 I. Skin of upper surface of head divided into several small shields. 



A. Mental barbels large, widening dis- 



tall}-, club-shaped ; plastron yellow 



with large black spots 1. hilarii, p. 222. 



B. Mental barbels narrow. 



1. Carapace with three tuberculate 



ridges in the halfgrown ; plastron 



with symmetrical black markings. 2. tuherosa, p. 223. 



2. Carapace with a single keel. 



Mental barbels as long as the diameter of 



the eye, black at tho base ; head and neck 



with symmetrical black bands ; carapace 



pale brownish, vermiculated with black . . 3. rjeoffroyana, p. 223. 

 Mental barbels shorter than the diameter 



of the eye ; intergular shield shorter than 



its distance from the abdominals 4. (jihha, p. 224. 



