358 Mr. A. S. Woodward on the 



transversely elongated narrow bone, tapering as it reaches 

 the broken median crest of the cranium ; and this may 

 probably be interpreted as a parietal (pa.) meeting its fellow 

 in the median line. There may perhaps be a small supra- 

 occipital crest (x), but this is uncertain. In front of the 

 squamosal and supposed parietal only one bone can be 

 distinguished forming the rostral region, and this probably 

 consists of the pair of frontals fused with the mesethmoid. 

 Postero-laterally, where in contact with the hinder elements, 

 the bone exhibits radiating fibres like an ordinary frontal 

 membrane-bone (/>'.), but further forwards it becomes finely 

 punctate and rugose. Two facettes on the border above the 

 position of the orbit are probably for the overlap of the two 

 membrane-bones noted in the next specimen. The upper 

 part of the frontal profile is compressed to a sharp edge, bat 

 further down it displays a slight flattened concavity, while 

 the extremity of the snout is broken away. A small depres- 

 sion on the surface of the undoubted frontal bone seems to 

 represent a mucus-pit (m.). The basicranial axis, so far as 

 preserved (to the border of the hyomandibular), is straight 

 and parallel with the ridge of the cranial roof behind the 

 frontal angle. Its constitution is uncertain, but as a median 

 vertical lamina seems to extend from its upper face to meet 

 the excessively developed mesethmoidal plate (m.eth.), the 

 part preserved may possibly be a much-extended vomer (u) 

 like that of the Pycnodonts. It expands below the position 

 of the eye and forms a thickened plate, which is distinctly 

 concave on its oral face. The fossil is unfortunately cracked 

 along the middle of this face, and the plate cannot be very 

 satisfactorily studied ; but it bears an extraordinary resem- 

 blance to the concave plates of P. expansus described above 

 (p. 355, PI. XIII. fig. 2), while its aboral face, especially on 

 the left side (fig. la, w), exhibits the peculiar fine reticula- 

 tion already noted on the detached specimens. It must, 

 however, be admitted that the peculiar dentinal structure so 

 characteristic of Plethodus cannot be distinctly observed. Of 

 the mandibular suspensorium, the very deep and narrow 

 hyomandibular (hm.) is shown on each side, with a promi- 

 nence on its thickened hinder border for the suspension of 

 the operculum. The mandible (d) is rather fragmentary, but 

 shown on the right side to be comparatively short and deep, 

 implying a rather small gape. The right dentary bears 

 minute, obtuse, styliform teeth on the border, apparently 

 arranged in more than one series, while part of the inner face 

 of the left dentary displays the surface of attachment for a 

 dense cluster of minute teeth (t). Below the hinder end of 



