328 Prof. T). M. S. Watson on 



The oral surEnce supports a bone formed of fused tooth-bnses 

 wliicli exactly resembles tliat which rests on the pahuine. 

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



Ectopterygoid. — The ectopteryg'oid is the bone which hns 

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

 element attached to a groove in t])e outer margins of the 

 pterygoid and palatine. It bears a single row o£ small, 

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

 faces towards the inner surface of the suborbital, is covered 

 with a granulation 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 

 aiticulated skull, and in the specimen referred to a slight 

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

 one plane. 



Premaxilla. — The recognition of a complete series of 

 palatal bones shows that the curious median tooth-bearing 

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

 must be the fused ))rtemaxillae. 



In no. 39070 and other specimens in the British Museum . 

 it stands vertically at the end of the snout, with the elong.ited 

 teeth of its lower lateral corner directed downward. Its exact 

 mode of articulation is not, however, determinable. 



A Coelacanth from the Solenhofen stone, in the Royal 

 Scottish Musium, shows a similar premaxilla in situ. 



Sepfoina.vill(i(?). — Within the nasal cavity, lying freely, 

 dorsal to the ];revomers and below tiie dorsal surface, are a 

 pair of bones which together form an arched roof. I know 

 these otdy in transvtrse section, and can give no account of 

 their shape. They may be true septomaxilhje, but are more 

 prob.ibly ossitications in the etiimoidal cartilages. 



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

 general shape of the parietals is well known. Tiiey terminate 

 anteri')ily 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 a ligament. 



