380 EDWARD PHELPS ALLIS, JR. 
fossa therefore probably represents that chamber, the superior 
process of the prodtic of Macropoma then being represented in 
the sphenotic and pterotic of Polypterus. The inferior process 
of Macropoma gives off certain smaller processes, one of which, 
called the process ‘h,’ evidently corresponds to that posterior 
portion of the ascending process of the parasphenoid of Polyp- 
terus that passes dorsal to the foramen faciale (posterior opening 
of the trigemino-facialis chamber). Another process, called the 
process ‘i,’ corresponds to the lateral point of the base of the 
ascending process of the parasphenoid of Polypterus. The deep 
fossa said to lie posterior to the process ‘h’ would seem to be the 
large posterior opening of the canal that traverses the ascending 
process of the parasphenoid of Polypterus and which I have 
lately referred to as the posterior opening of the canalis para- 
basalis (Allis, ’18). 
The lateral surface of this portion of the neurocranium of 
Macropoma thus evidently quite closely resembled that of 
Polypterus, and this would naturally suggest that there should 
also be some resemblance in the bones related to its ventral 
surface, and if Huxley’s figure (l.c., fig. 3, pl. 8) of that surface 
of the skull of Macropoma be compared with my figure (’00, 
text fig. 1), giving a similar view of the skull of Polypterus, there 
is seen to be a marked similarity. The anterior portions of the 
parasphenoids of the two fishes are strikingly similar, and on 
either side of that bone there is, in Macropoma, a single tuber- 
culated bone, and in Polypterus two such bones, both related 
to the palatoquadrate. Along the lateral edge of the single 
bone of Macropoma there is a dentigerous bone that Huxley 
considered to be the maxillary, the posterior portion of the 
maxillary of Polypterus having similar relation to the lateral one 
of the two bones of that fish. Anterior to the lateral one of 
these two bones of Polypterus, and overlapped ventrally by the 
anterior end of that bone, there is a palatal process of the max- 
illary, and in Macropoma, in strictly similar position, there is 
a bone that Huxley calls the palatine. No teeth were found on 
this bone in the specimen of Macropoma used by Huxley for the 
figure given, but teeth apparently belonging to it were found by 
