294 Mr. A. S. Woodward on the 



digitating with the frontal (seen also in no. P. 6904). The 

 squamosals (sq.), though considerably crushed and fractured 

 in the specimen figured, are observed to be much larger than 

 the parietals and extend further forwards. The frontals 

 (/r.) are relatively enormous, uniting in an irregular, often 

 interdigitating mesial suture, the outer surface especially 

 rugose in their anterior half, and irregularly marked with 

 rows of pittings which appear to be connected with the 

 sensory canal-system. It is not quite clear whether the 

 ossified postfrontal appears behind, but the prefrontal is ex- 

 posed in front (PI. VIII. fig. 2, ;"'./.), and between these 

 two elements the frontal is bordered by an irregular series of 

 supraorbital plates (PL VIII. figs. 1, 2, sp.o.), which are 

 continued extensively down upon the cheek as a patch of 

 antero-posteriorly elongated tesserjB (PI. VIII. fig. 2, t.). 

 This arrangement can also be seen in the typical species, 

 Caturus farcatus, from the Bavarian Lithographic Stone (e. g. 

 specimen in Brit. Mus., no. P. 908). The nasal bones 

 (PI. VIII. figs. 1, 2, na., and PI. IX. figs. 4, 4 a) are small, 

 antero-posteriorly elongated, externally tuberculated, and 

 exhibit the usual little lateral process in the anterior half of 

 their outer margin. One specimen (PI. VIII. fig. 2) suggests 

 that a very small, transversely elongated, bilaterally symme- 

 trical membrane-bone [x) also covered the rostral end of the 

 mesethmoid ; but this little element is crushed and tractured. 



Facial Bones, Jaws, and JJyoid Apparatus. 



The check is completely covered with thin plates. Imme- 

 diately in front of the preojierculum are two very large 

 plates of the suborbital (postorbital) series (PI. VI II. fig. 3, 

 S.O.). Two circumorbitals (c.o.), the lower broad and the 

 upper narrow, separate these from the orbit, and there is a 

 small scries beneath the eye. There is also at least one 

 antorbital plate (PI. VIII. fig, 3, a.c). The supraorbitals 

 have already been described, and it only remains to add that 

 portions of an ossified sclerotic can often be observed within 

 the cavity of the orbit (PI. VIII. fig. 3, scl). The hyo- 

 mundibular (PI. IX. fig. 1, hm.) is large, much laterally 

 compressed and expanded, with a considerable process {p.) 

 for the support of the operculum. Tiie quadrate (PI. IX. 

 fig. 1, qu.) is triangular, meeting the front half of the lower 

 margin of the hyomandibular, and doubtless bordered behind 

 by an ossified symplcctic, which has not yet been seen. The 

 articular head of the quadrate is especially robust, with a 

 concave facette for the articulation of the mandible. The 



