342 D. M. 8. Watso7i — On Micropholis Stowi, Huxley, 



Micropholis we have an early condition where the duct is still in the 

 skin and has not yet sunk at all deeply. 



(h) The very great forward extension of the duct and its very 

 unusual exit, practically on the outer surface and just behind the 

 septomaxilla, are of interest. The duct only occurs in Tetrapoda, 

 never in fish, and its origin is obscure ; it may be suggested that it is 

 possible that it has been derived from one of the lateral line canals 

 so commonly found in Stegocephalia, of which there is no trace in 

 MicropJiolis. 



The jugal is very small ; it lies along tlie upper edge of the maxilla, 

 and its anterior end is united by a suture to the lachrymal. Its 

 slender posterior end jiist meets the anterior end of the post-orbital 

 in the middle of the lower border of the orbit, the two bones being 

 covered outside by the maxilla. 



The post-orbital is a very large bone forming a great deal of the 

 posterior and lower borders of the orbit, having a very extensive 

 suture with the maxilla and also touching the jugal and quadrato-jugal. 



4. In the temporal region the three bones squamosal, intertemporal, 

 and supratemporal are present. The squamosal has its usual relations, 

 the sub-otic part of the bone sheathing the back of the quadrate and 

 meeting the pterj'goid. The other two bones are not in relation to 

 any underlying bones and are remarkable in that the posterior bone, 

 the supratemporal, is much reduced, covering a very small area 



Fig. 2. Micropholis Stoioi. Side of face. X 2. From a Geological Society 

 specimen. The dotted lines in the lachrymal mark the course of the 

 ductus naso-lachrymalis. 



between the squamosal, intertemporal, and tabular. In every other 

 Stegocephalian that I remember the intertemporal is the bone which 

 is reduced, the supratemporal remaining large. 



The palate (Text-fig. 3) is beautifully shown in Owen's type- 

 specimen. 



The basi-occipital has not been seen, but R. 510« shows well the 

 two large exoccipital condyles, from above and the back. The 

 basisphenoid is not well shown, but has large laterally directed 

 basipterygoid processes with which the pterygoids articulate. 



There is a large parasphenoid forming a plate much higher than 

 wide, whose upper edge is channelled to receive the cartilaginous 

 mesethmoid. The lower surface of the parasphenoid bears a double 

 row of small backwardly directed sharp teeth. 



The pterygoid articulates loosely with the basipterygoid process of 

 the basisphenoid, sends a ramus, which consists of a deep narrow 



