77 
but extends well forward, and in Trimerorachis as far forward as in 
almost any reptile. I cannot speak of the condition in Peloneustes 
mentioned by Watson, but I do not agree with his statement that 
the Coronoid in Dicynodon “actually reaches the symphysis”. In 
Dicynodon, as I interpret the structure, there is no Coronoid at all. 
The part believed by Watson to be Coronoid is in my opinion part 
of the Dentary. I have examined a large number of specimens and 
can’t assure myself of any element in this region that is not Splenial, 
Dentary, Surangular or Prearticular. 
For the anterior Coronoid element in the Stegocephalian jaw, I 
propose the name Precoronoid. 
Watson and SMITH Woopwarp have pointed out that the Splenial 
of the Stegocephalian jaw is apparently homologous with the first of 
the Infradentaries of the Cros- 
sopterygian mandible. And 
Watson has shown that in the 
very primitive Loxomma the 
Splenial is still almost entirely 
a bone of the outer side of the 
jaw. He has further called 
my attention to the fact that 
the Surangular and Angular 
are also other Infradentaries 
of such a jaw as Rhizodopsis 
or Megalichthys. The presence St \ 
in the Stegocephalian jaw of a 
a Preangular of which Watson Fig. 4. Shoulder girdle and bones of 
d pectoral fin of Sauripteris taylori. About 
was not aware renders the 1/, nat. size. Cleith. Cleithrum ; Sc. Scapulo- 
resemblance of the jaw to that coracoid ; H. Humerus; U. Ulna ; R. Radius ; 
- p Piriform; w Ulnare; 7 Intermedium ; 
of the Crossopterygian much 3. Radiale. 
more striking. 
The structure of the jaw in the Osteolepidotous Crossopterygian 
is not very fully known. Traquair has figured the front of the outer 
side of the jaw in Rhizodopsis and Warson has found a very similar 
condition in Megalichthys, but practically nothing appears to be known 
of the back of the jaw or of the inner side. In the American Museum 
there is a specimen which adds a few more facts to our knowledge. 
This is the specimen described by Haut as Sauripteris taylori. Though ~ 
very imperfectly known, it is manifestly a pretty near ally of Rhizod- 
