328 Prof. D. M. S. Watson on 



Tlie oral surface supports a bone formed of fused tooth-bases 

 wbich exactly resembles that which rests on the palatine. 

 Tlie large tusk is, however, placed at the caudal end. 



E do pterygoid. — The ectopterygoid is the bone which has 

 usually been called maxilla. If is a long, very delicate 

 element attached to a groove in the outer margir)S of the 

 pterygoid and palatine. It bears a single row of small, 

 recurved, sharp-pointed teeth, and its outer surface, which 

 faces towards the inner surface of the suborbital, is covered 

 with a grauulatiou of small denticles like those on the 

 pterygoid. 



It is quite clear that this element cannot be the maxilla, 

 because there is no evidence of the attachment of any bone to 

 the lower margin of the suborbital. 



That in B. M. N. H. no. 39070 (A. S. Woodward, pi. xxxv. 

 fig. 10) it lies below and parallel to the suborbital is explained 

 by the fact that the outer margin of the pterygoid is very 

 nearly parallel to the lower edge of the suborbital in the 

 articulated skull, and in the specimen referred to a sliglit 

 inward disp'acement of that bone has brought the two into 

 one plane. 



Premaocilla. — The recognition of a complete sei'ies of 

 palatal hones shows that the curious median tooth-bearing 

 element X of Huxley's figure and Smith Woodward's vomer 

 must be the fused prtemaxillfe. 



In no. 39070 and other specimens in the British Museum 

 it stands vertically at the end of the snout, with the elongated 

 teeth of its lower lateral corner directed downward. Its exact 

 mode of articulation is riot, however, determinable. 



A Coelacauth from the 8olenhofen stone, in the Royal 

 Scottish Must'Um, shows a similar premaxilla in situ. 



Sep(omaxilla{?). — Within the nasal cavity, lying freely, 

 dorsal to the prevomers and below the dorsal surface, are a 

 pair of l)Ones which together form an arched roof. I know 

 these only in transvt^r.se section, and can give no account of 

 their shape. They nuiy be true septomaxilL'B, but are more 

 probably ossitications in the ethmoidal cartilages. 



Dermal Bones of the Outer Surface of the Head. — The 

 general shape of the parietals is well knowii. They terminai,e 

 anteriorly in a transverse margin whose edge is rounded, 

 entirely unlike a suture and always separated from the 

 similar hinder edge of the frontal by a space. 



Ttiere is, in fact, no doubt possible that the Coelacanths 

 had a movable joint between these two bones, which were in 

 life connected by u ligament. 



