HR. GIUNTHEB ON THE ANATOMY OE HATTEEIA. 
599 
depression across its middle : and there is a very singular wide foramen above the condyle ; 
it is filled with loose cellular tissue. 
The columella (p) arises from above the suture between the pterygoid and quadrate 
bones; it differs in its form from that of other Lizards, being very broad (8 millims.), 
spatulate at its upper and lower ends, and constricted in the middle. Being fixed by 
an irregular suture to the pterygoid and quadrate, and attached to the parietal by a 
narrow strip of cartilage, it contributes materially to the solidity and immoveability 
of the pterygo-tympanic arch. A crescentic space between alisphenoid and columella 
remains cartilaginous ; and the fore part of the cranial cavity is closed by fibro-cartilagi- 
nous membrane without a trace of ossification. 
The maxillo-palatal portion of the skull offers no less peculiarities than the parts 
described before. The intermaxillaries are paired ; their posterior portion is tapering 
and wedged in between the nasals ; there is no discontinuity of the osseous substance 
whatever on the upperside of the snout, the nostril being entirely lateral ; the fore 
part Qf the nasal opening is formed by the intermaxillary. This bone resembles in 
some measure that of a Rodent, each half being armed with an extremely strong incisor 
as broad as the bone to which it is anchylosed. The horizontal part of the maxillary 
is extremely narrow, reduced to a simple although strong alveolar ridge ; its ascending 
nasal process is (with the nostril) much advanced forwards, in the anterior third of the 
bone. The foramina maxillaria superiora are present as in other Lizards. 
The vomer {q) is paired, each half being of an elongate triangular shape, broader behind 
than in front ; it forms nearly entirely the inner edges of the choanse, and its posterior 
extremity is even behind their level. Most singularly it is in immediate contact with 
the front part of the pterygoids (r)*, which thus prevent the palatines (s) from reaching 
the median line of the palate. 
The palatine bones (s) are entirely separate from each other, each being closely united 
by suture to the posterior two-thirds of the maxillary ; and being armed along its maxil- 
lary margin with a series of teeth similar and parallel to that of the maxillary, the two 
series are in close proximity, so as to give to the maxillary the appearance of having a 
double dentigerous ridge. The inner part of the palatine is unusually broad, participating 
but little in the formation of the choana, from which it is shut out by the vomer, but 
forming about one half of the bottom of the orbit, which is rendered almost completely 
osseous by the accession of the pterygoid, zygomatic, and os transversum. 
The pterygoid bones (r) are suturally connected with the vomer, separated in the middle 
by a comparatively narrow cleft, meeting again where they are immoveably joined to 
the basisphenoid processes ( f) which are close together, and finally suturally attached to 
the quadrate bone as described above. They are toothless, but traversed in their middle 
* The perfect preservation of the sutures in a specimen prepared by myself has enabled me to point out this 
very unusual arrangement of the bones of the palate. Professor Owen designated, in Rhynchocephalus, 
bones according to the position usually occupied by them in Lizards, viz. the front part of the pterygo 
palatines, and the palatines as palatal plates of the maxillary. 
