604 
DE. GUNTHER ON THE ANATOMY OF HATTEEIA. 
mens, that Hatteria is very slow and sluggish in its movements * ; therefore its food must 
chiefly consist of other Lizards of similarly sluggish habits, and young birds or insects 
accidentally approaching its mouth. Young specimens feed probably on insects only. 
Before I proceed to the description of the trunk of the skeleton, I may be allowed to 
recapitulate the peculiarities in the structure of the skull ; they are — 
1. Persistence of the sutures, especially of those between the lateral halves of the 
skull, combined with a great development of its ossified parts as it appears in the 
expanse of the bones forming the upperside of the facial portion, in the completeness 
of an orbital ring with a temporal and zygomatic bar (Crocodilia), in the much expanded 
columella, in the completely osseous bottom of the orbit, and in the almost continuous 
roof of the palate — the palato-narial and interpterygoid vacuities being very narrow. 
2. Firm and solid union of the os quadratum with the skull, and of the bones of the 
palate with the quadrate, as shown by the sutural connexion of quadrate and pterygoid, 
broad sutural connexion of the columella with quadrate and pterygoid, immoveable 
pterygo-sphenoid joint, firm and extensive attachment of pterygoid to ectopterygoid. 
3. This restriction of the mobility of the bones named is compensated by an increased 
and modified mobility of the lower jaw, the mandibles being united by a ligament and 
provided with an elongate articular surface. 
4. Displacement of the palatine bones which are separated by the pterygoids, and 
replace a palatal portion of the maxillaries. 
5. Dentition unique, viz. : — two large cutting teeth above, formed by the confluence of 
two pairs of conical “ milk ’’-teeth ; alveolar edges of the jaws and palatines cutting 
and polished (in the adult), only partially armed with teeth (forming a serrature) ; pala- 
tine teeth in close proximity and parallel to maxillary series, both series receiving between 
them in a groove the similarly serrated edge of the mandible. 
6. Finally, perforation of quadrate bone and extremely short postarticular process of 
mandible. 
The Vertebral Column. 
Professor Owen has discovered the biconcavity of the vertebraef (figs. 19, 22, 23). 
Those of the trunk (from the third cervical vertebra to the fourth or fifth caudal) are 
distinguished by their uniformly developed, strong and compressed neural spines, which 
become more slender and remote on the tail, disappearing only on about the last ten 
vertebrae. The total number of vertebrae is 63, viz. : — 
3 cervical (1-3) without pleurapophyses. 
5 cervical (4-8) with pleurapophyses. 
3 dorsal (9-1 1) with ribs attached to sternum. 
11 dorsal (12-22) with ribs and abdominal ribs. 
3 lumbar (23-25). 
* I am indebted to Sir Andrew Smith for tbis observation, 
f Catal. Osteol. Ser. Roy. Coll, of Surgeons, vol. i. p. 142 (1853). 
