1904.] LABYRINTHODONT SKULLS. 175 



broad plates ; while the vomers (vo.) bound the antero-posteriorly 

 elongated posterior nares (ptn.) both behind and within. The 

 only teeth observable are indicated by an impression of the middle 

 part of the pterygoid region (fig. 5), where they occur chiefly in 

 two close parallel rows, one on the outer edge of the pterygoid 

 (pt.), the other on the maxilla (mx.). The teeth of each series 

 are nearly uniform in size, but those of the pterygoid are some- 

 what larger than those of the maxilla. They are all cones with 

 the usual thickened and folded walls. There are also traces of an 

 irregular patch of minute teeth or tubercles still further back on 

 the pterygoid. 



Three vertebral centra found in the same formation and locality 

 as the skull are deeply-biconcave discs, not pierced by any foramen 

 for tlie passage of a remnant of the notochoi-d. One obliquely 

 crushed specimen is shown of the natural size in PI. XII. fig. 8, 

 and another impeifect specimen is similarly represented in fig. 9. 

 The concavity at the end of the centrum is very slight near the 

 outer rim and suddenly deepens towards the centre. 



It is difficult to determine the precise affinities of so frag- 

 mentary a Labyrinthodont skull, but if the vertebi-al centra are 

 rightly ascribed to the same animal, it evidently represents one 

 of the higher members of the Order. Though suggestive in some 

 respects of Gricottos, as already mentioned, the new skull difiers 

 from that of Cope's genus in the thickening or depression of the 

 middle part of the parietals, and in the very strong external 

 sculpture. The associated vertebral centra also difier from those 

 of Gricotus in being completed discs. Among other Labyrintho- 

 donts, the specimen from Spitzbergen seems to approach most 

 closely the skull of Trematoscmrus *, with which it agrees in its 

 general shape, external sculpture, dentition (so far as seen), and 

 the relations of the quadrate bone. It is distinguished, however, 

 by the peculiar disposition of the parietal bones. The new fossil 

 thus represents a hitherto unknown genus, which may be named 

 Aphaneyamvia and defined as follows : — Skull elongate-triangular, 

 with the orbits widely separated and situated in its hinder half ; 

 external bones strongly sculptured, and grooves for slime-canal 

 deep. Parietal bones extending forwards between the orbits ; 

 frontals very long and narrow : both these elements excluded 

 by the postfrontals and prefrontals from the orbital border. 

 A single regular row of small teeth on the pterygoid parallel 

 with the equally uniform row of teeth on the maxilla ; clustered 

 small teeth or tubercles further back on the pterygoid. Vertebral 

 centra complete biconcave discs, not perforated. The type- 

 specimen of the type-species, A. rostratum, is the imperfect skull 

 now described. 



* H. Bui'meister, ' Die Labyriutliodonten aus dem bnnten Saudstein von Bern- 

 burg,' pt. i. (1849). Tlie minute posterior pteryajoid teeth are seen in a specimen of 

 Trematoscmrus in the British Museum (no. R. 1733) and in one in Mr. W. E. 

 Balston's collection. 



