334 Prof. D. M. S. Watson on 



jaw and visceral arches, wliicli we have seen to be neoinorphs 

 without morphological importance. At the same time, I think 

 it })robable that we have in Macropoma the beginning ot" the 

 process which results in Teleosts in the production of an 

 auto- and a dermo-pahitine : all I wish to make clear is that 

 the [)alatine of Coelacauths is not to be regarded as an original 

 ossitication in the palato-quadrate cartihige. 



'JMie so-called pre-ethmoid of Coelacauths reseml)l(;s in 

 structure the palatine, with which it articulates, and, lik^ that 

 bone, supports a tooth-plate. In position on the palate and 

 in the associated teeth it recalls the prevomer of an Osteolepid. 

 I am extremely doubtful of its being an ossification on the 

 nasal capsule, and prefer to regard it as a prevomer, fully 

 recognizing that it is very unusual in passing on to the 

 dorsal surface of the parasphenoid, in extending so far 

 dorsally over the side of the olfactory capsule, and in its 

 perforation by a foramen. 



The ectopterygoid is identified without difficulty. 



The accurate determination of the homologies of the dermal 

 bones of the outer surface of the head in Coelacanths seems 

 to me at present impossible. Only in Osteolepis, Megalichlhys, 

 Eusthenopteron, and Dictyonosteus is the structure of tlie 

 snout known at all. In Osteolepis and Megalichthijs, where 

 I have been able to examine considerable numbers of good 

 specimens, the number and arrangement of the bones in tlie 

 anterior region of the skull vary enormously ; in the latter 

 genus especially they are seldom symmetrical, and I prefer 

 not to attach independent names to them. 



The skull of Eusthenopteron represented in Stensio's (ig. 57 

 difi'trs very greatly from Bryant's restoration, whicii is borne 

 out by his photogiaphic plates, and in the passage of the 

 supratemporal cross-connuissure of the lateral line a[)paratus 

 over the tabulare and interparietal differs from all (Jsteokpid 

 skulls I have ever examined. 



Macropoma clearly presents a multiplication of dermal 

 bones, and is not a favourable subject for study ; but I think 

 it probable that the peculiar bone with a downwardly directed 

 process and the second paired parafrontal are separated {)art3 

 of JSteysio's nasalo-antorbital, and that the process separated 

 the tw*o narial apertures. 



One of the most sti iking characters of the Coelacanth skull 

 is the hinge between the parietals and frontals, which is in 

 Macropoma continued outwards between bones of the para- 

 Irontal series. 



Tliis hinge is exactly similar to that which occurs in an 



