Chelonia. 
39 
Here are placed tlic fossil remains of the order Chelonia, 
most largely represented at the present day, including Hie 
Tortoises and Turtles, a group of reptiles in which the verte- 
brae and ribs are immovable, being combined with the external 
coat of bony plates, closely connected by interlocking sutures, 
Wall-cases, 
Nos. 11 & 12, 
and Table- 
cases, 
Nos. 20, 21, 
and 22. 
Fig 48 — Outline of the Carapace, or dorsal Fig. 49. — The plastron, or ventral shield, of 
shield" of Hardella Thurqi (Gray), reduced. Cachuga tectum (Gray), reduced ; ep., epiplastial 
IU n ’ uc hal- nl-nS neurals’; cl-c8 costals; spy, bone ; entp., entoplastral bone ; hy.p., hyoplastral 
1 & 2 sun’rapygals; pv, pygals ; ml-mll, mar- bone; xp., xiphiplastral bone; g gular shield; 
iinals“" In both these figures the outlines of the hum., humeral; pec., pectoral; ab., abdominal; 
bones have wavy sutures, * ®thc firm dark hues show fem., femoral ; and an., anal shields, 
the outlines of the overlying horny shields. 
Figs. 48 and 49 are both from the Pliocene, Siwalik Hills, India. 
enclosing the entire body of the animal. This box-like 
envelope is covered with leathery skin or horny shields ; one 
kind of which is called “tortoise-shell,” and is made into 
combs, &g. The bones of the skull (except the lower jaw and 
the hyoid bones) are also consolidated. They have no teeth, 
but the jaws being encased in a horny beak, the sharp edges 
serve instead for dividing the food. 
The Chelonians are found living at the present day on land, 
in fresh water, and in the sea; they are all oviparous, depositing 
their eggs in the sand, to be hatched by the warmth of the sun. 
Some recent Turtles’ eggs from Ascension, cemented together JJ 12> 
and fossilized in shell-sand hj deposition of lime (produced 
through the rapid evaporation of the sea-water by the suns 
heat) , 3 are exhibited in Wall-case, A T o. 12. 
