woodward: fossil fishes of the upper lias of WHITBY. 463 
the extreme right above, the imperfect parasphenoid {j^as.) hes 
horizontally with exposed inferior face and its bifurcating 
posterior end turned to the left. Its anterior end is seen to 
be slightly expanded, but its middle portion is obscured by a 
transverse fracture. The hyomandibular bone {hm.) of each side 
is preserved, the one at the extreme left above, slightly over- 
lapped by the clavicle (c^.), the other at the left lower angle 
of the slab. Two slender, hour-glass-shaped bones, about as long 
as the hyomandibular, are probabl}^ the pair of ceratohyals (ch.). 
Other more imperfect and more slender rod-shaped bones may 
perhaps represent the branchial arches. Various fragments 
of plate-like bones (e) exhibit traces of coarse tuberculations 
Fig. 2. — Gyro.^teus mirahi/i.s, Ag., MS.; imperfect parasphenoid, inferior 
aspect, one-fourth nat. size. [Brit. Mus., No. P. 2262a.] (From Catal. 
Foss. Fishes, B.M.) 
Fig. 3. — Parasphenoid of recent sturgeon (Acipenser), inferior aspect, much 
reduced. (From Catal. Foss. Fishes, B. M.) 
