Dr. J. E. Gray on Chelonians. 303 



the caudal marginal bones large, oblong, transverse, the 

 hinder side being separated by an arehed suture from the upper 

 hinder margin of the penultimate marginal bone. 



*** The second vertebral plate with broad projecting front lateral 

 angles, which are much wider than the first vertebral plate. 



3. Hydromedusa Bankce, Giebel, Zeitsehr. f. ges. Naturw. 

 1866, t. iv. 



The front marginal plates square, four-sided, rather broader 

 than long. First vertebral plate oblong, more than twice as 

 wide as long, truncated at the sides, rather widening behind, 

 as broad in front as the two front marginal plates, the hinder 

 edge arched ; the second vertebral plate as long as broad behind, 

 much wider in front, with the front lateral angles produced 

 beyond the sides of the front vertebral plate, and angular, with 

 two short sides, the sides straight and gradually contracting to 

 the width of the next* plate ; the other vertebral plates six- 

 sided, not quite so long as broad. The hinder vertebral and 

 costal plates do not appear to be tubercular. 



Hah. " Island of Banka" {Giehel). 



II. Chelomedusa. 



Head moderate, back of neck tubercular. Front pair of 

 marginal plates subtriangular, broad on the inner side, narrow 

 on the outer side ; the first vertebral plate narrow in front, 

 and as wide as the four marginal plates, wide behind, with 

 shelving sides. 



The hinder vertebral and costal shields not tubercular. 

 Sternum flat. The head and upper part of neck dark brown, 

 the upper lip and midersides of head and neck white. 



* The second vertebral plate moderate, with a narrow projecting lobe 

 on the front lateral angle, as wide as the first vertebral plate. 



4. Hydromedusa depressa^ Hand-list Sh. Rept. p. 64. B.M. 



Front vertebral plate very short, transverse, narrow in front, 

 twice as broad behind, and angular at the ends ; the second 

 vertebral plate four-sided, longer than broad, with a small pro- 

 jecting lobe at the front lateral angle, projecting as far as the 

 hinder edge of the front vertebral plate. The front pair of 

 marginal plates moderate, longer than broad. The costal and 

 dorsal plates with a brown spot on the hinder part, without 

 any tubercle. 



Sternum flat ; the front plates irregular in this specimen. 

 Gray, Cat. Shield Kept. p. 60, t. xxvi. 



Hah. Brazil [Brandt). 



