46 SPHARGIS CORIACEA. 



Description. The carapace is sub-cordiform, largest before and deeply con- 

 cave over the neck; concave also over each of the anterior extremities, but less 

 so. It is narrow and pointed behind and above, and is marked with seven longi- 

 tudinal carinEB: one of these runs along the vertebral line, throughout its whole 

 extent; on each side of this are three other ridges, the external on each side 

 following the margin of the carapace from its anterior to its posterior extremity, 

 where they meet above the tail in a point. The surface between these ridges is 

 perfectly smooth. 



The sternum is large, very full in front, and truncated squarely, smaller and 

 obtuse-angled behind: it is perfectly flat, without any prominence or tubercle 

 whatever. 



The head is very large, sub-triangular, slightly compressed in front and above, 

 without plates or scales, and covered only by the skin. The jaws are exceedingly 

 strong, the superior with three deep triangular notches in front; the inferior is 

 recurved anteriorly in an angular point, which is received into a central notch of 

 the upper jaw when the mouth is closed. The nostrils are anterior, and near 

 together. 



The neck is short, very thick, and covered with a coriaceous skin, and at the 

 throat are a few depressed tubercles. 



The anterior extremities are large and well developed; they are twice the 

 length of the posterior, which are broader in proportion; both are covered with 

 a coriaceous skin — neither have any trace of nails. The tail is short, and 

 extends but little beyond the carapace. 



Colour. The whole superior surface oi' the animal is very dark brown, with 

 the exception of the ridges on the back, which are tinged in different places with 

 obscure dirty white. In the young Sphargis coriacea the colour is less dark, and 



