188 



articular convexity looking downwards : in the antecedent cervicals the posterior zygapo- 

 physes are supported on a semicircular horizontal plate overlapping the intervertebral space : 

 the bodies of all the cervical vertebrae are much compressed and carinate inferiorly, and this 

 is particularly the case with the last. The short pleurapophyses of the first dorsal vertebra 

 ascend obliquely outwards and backwards to aid in propping up the carapace. The long 

 scapulae abut against these, in which respect the vertebra may be compared with a sacrum : 

 the other vertebrae of the carapace offer the usual modifications and combinations with the 

 neural and costal plates. The neural canal sinks into the substance of the centrum of the 

 second to the ninth dorsal vertebrae, and merely grooves the inferior interspace of the neur- 

 apophyses ; the expanded trihedral summits of the iliac hones abut against broad sutural 

 surfaces on the under part of the last costal plates, and are barely touched by the rudimental 

 ribs of the two sacral vertebrae. The iliac bones articulate by the whole of their under sur- 

 face to the xiphisternals, and the pubis is anchylosed to the same by the thick process given 

 off from its outer surface. The scapular arch articulates with the carapace by the scapula, 

 and to the plastron by its acromial process, but the coracoid is free and expanded for the 

 attachment of the muscles, which rotate the arch horizontally upon its two attached points. 

 The elasticity of the scapula and acromion, and the angle at which they are placed, permit a 

 slight approximation of the borders of the anterior outlet of the osseous box. 



In the fore-foot the scaphoid is represented only by its median portion ; the lunare articu- 

 lates with boh radius and ulna ; the cuneiforme is small, the pisiforme is wanting ; the fifth 

 digit is rudimental ; the other four are armed with long and strong claws ; the thumb has 

 two phalanges, each of the others three. In the hind-foot the astragalus and scaphoid form 

 a single large bone ; but there is a distinct rudiment of a calcaneum : the bones of the second 

 tarsal row progressively increase in size from the tibial to the fibular side : the two bones repre- 

 senting the cuboid are distinct, the outermost is broad and flat, and supports the rudiment of 

 the fifth toe : this is clawless, but has two phalanges : the other digits have long and strong 

 claws, the hallux having two phalanges, the rest three, as in the fore-foot. 



Hunterian. 



Genus Einys. 



962. The skeleton of a freshwater Tortoise (Emys). 



The carapace is less convex than in the genus Testudo, but is equally well ossified, and the 

 second and fifth of the costal plates articulate directly with the hyo- and hypo-sternals, com- 

 pleting the haemal arches there without the interposition of the marginal pieces. The second 

 to the fifth costal pieces of the right side have been disarticulated, so as to expose the interior 



of the carapace. 



Mus. South. 



963. Disarticulated portions of the carapace of a small freshwater Tortoise (Emys). 



Some of the parts are wanting ; the short pleurapophyses of the first vertebra of the cara- 

 pace, for example : the costal plates connate with succeeding pleurapophyses, forming the 



