466 woodward: fossil fishes of the upper lias of whitby. 
of one-third the natural size in fig. 4. The bone is much 
constricted somewhat above its middle. Its comparatively small 
upper portion is compressed antero-posteriorly, while its much 
expanded lower portion is still more compressed laterally. It 
thus resembles the hyomandibular of the modern sturgeon in 
shape, only differing from the latter in the greater extent of 
the ossification in its lower expanded portion. 
Figs. 7, S.—Gyro.^tei(.^ mirahi/is, Ag., MS.; ceratohyals, one-third nat. size. 
[Brit. Mus., Nos. P.2262f, 43304.] 
Of the maxilla only a single example is yet known, in 
the collection of the late Earl of Enniskillen (Brit. Mus., 
No. P. 3356?). It is of the left side and an outer view of it 
is gi^^en in the accompanying fig. 5. It differs considerably in 
