490 A. Smith Woodward—On the Genus Anomeodus. 
ramus, and was obtained from the Lower Chalk of Glynde, Sussex. 
It is shown in side view, of two-thirds the natural size, in Plate 
XVII. Figs. 1, la; while the splenial and vomerine dentitions 
are represented of the natural size in Figs. 16, Je. 
The skullis much elongated, and the snout must have been acutely 
pointed. The median septum in the rostral region is robust, with 
a slight horizontal expansion at its upper edge; and the limits of 
the ethmoidal bone (e.) are indicated by the fact that its structural 
fibres are directed downwards and forwards, while those of the 
vomer (v.) are horizontal. The vomer appears to have been single, 
and bears teeth, as already described (Fig. 1c). Of the cranial roof 
only one bone is preserved, a long smooth element on the left side 
(Fig. la, fr.), evidently to be regarded as frontal. 
At the hinder extremity of the vomer, a short distance beyond the 
limit of the dentition, there is seen the pterygo-quadrate-palatine 
arcade (Fig. 1, pt.); and throughout the length preserved, this is 
shown to form a continuous, inwardly-curved thin plate fused with 
the base of the skull (perhaps with the edge of the parasphenoid). 
The posterior part of the fossil also exhibits a thin median plate 
(Fig. 1, pas.) descending from the inferior face of the parasphenoid. 
The constituents of the pterygo-palatine arcade cannot be dis- 
tinguished; but its anterior thickened margin, with a re-entering 
angle, is shown on the right side (Fig. 1), and the robust quadrate 
articulation, much deeper than broad, with its hollowed facette 
for the attachment of the mandible, is preserved on the left 
(Fig. la, qu.). To the postero-external border of the quadrate and 
its supporting bones on each side, there is also firmly fixed an outer 
element, with rugose surface, much expanded below and contracted 
above, which evidently occupies the situation of a pre-operculum 
(p. op.). Its correct shape is shown on the left side (Fig. la, p. op.), 
and this seems to be the bone already described in Gyrodus as 
‘“‘maxilla.”* ‘The imperfect mandible is also shown, a fragment of 
the right ramus being displaced to the extremity of the snout 
(Fig. 1), and the left ramus being nearly complete, though much 
fractured (Fig. la, md., Fig. 1b.). The structure of the mandible 
is not clear ; but the articular element (Fig. 1b, ar.) exhibits a very 
deep undulating facette, and on the splenial (spl.) the dentition 
appears to be restricted to a surface considerably within the external 
margin of the bone. 
Between the two jaws there are also remains of stout bones, 
perhaps of the hyoid arch, but these are insufficient for determination. 
To summarize, the skull of Anomeodus Willetti shows that (i) the 
vomer is single; (ii) the mandibular suspensorium is strongly 
inclined forwards; (iii) the pterygo-palatine arcade is delicate, 
toothless, and fused throughout the greater part of its length with 
the base of the skull; (iv) the parasphenoid has a deep inferior 
lamellar keel; (v) the articulation of the mandible is very deep 
and narrow; and (vi) there is a large superficial bone apparently 
' A. Wagner, Abhandl. k. bay. Akad. Wiss., math.-phys. Cl., vol. ix. (1862), 
p- 826. Also K. A. von Zittel, “‘ Handb. Paleont.’’ vol. iii. (1887), p. 239) fig. 251. 
