Squcimata — Ophidia and Lacertilia. 
25 
(concave in front), although more rarely they are amphicoelous 
(bi-concave). True abdominal ribs are never developed. The 
< arpus lias but a single centrale, and the precoracoid process is 
often well marked. 
Sub-order 1 .— Ophidia (Serpents). 
Serpents are rarely met with in a fossil state, but a few 
such remains have been obtained from the Tertiary rocks. T lie 
earliest Ophidian* represented in the Collection is the JPalceophis 
A 
B 
c 
Fig. 2D. — Vertebrae of Palceophis typhceus (Owen), from the Lower Eocene, Sheppey. 
A, haemal; b, anterior; and c, left lateral views of a trunk vertebra, wanting most 
of the neural spine; z s, zygosphene ; c, costal articulation. 
toliapicus , a serpent about 12 feet in length, obtained from the 
London Clay of Sheppey ; from the Middle Eocene of Brack- 
lesliam we have a still larger form, the Palceophis typhceus, a boa- 
cons trie tor- like snake, considered to be marine, that attained a 
length of 20 feet, and also a smaller species, P. porcatus. 
ABC 
Fig. 30.— (A) Haemal, (B) Anterior, (C) left lateral views of a trunk-vertel»ra of 
Paleryx rhombifer (Owen), from the Eocene Phosphorites of Caylux, France, 
c, costal articulation ; z, s, zygosphene. 
The Upper Eocene sands of Hordwell have yielded numerous 
vertebra? of snakes, but of a much smaller size, namely , 1 aleiyx 
rhombifer and P. depressus. Others are recorded from the 
Miocene of CEniugen and the Lignites of Bonn-on-the-Rlnne, and 
are exhibited in this case. 
Sub-order 2.— Lacertilia (Lizards). 
The earliest known member of the large group of existing 
Lacertian reptiles is Macellodus (with which Saurillus is pro- 
bably identical, or closely allied), mostly known by jaws and teeth 
* M. Sauvage lias described Ophidian Vertebree from the Chalk of France. 
Serpents. 
Table-case, 
No. 11. 
Palaeophis. 
Paleryx. 
Lizards. 
Table-case, 
No. 12. 
