woodward: fossil fishes of the upper lias of WHITBY. 465 
is possibly an overlapped surface. The largest bones in the 
group are the left clavicle (cl.) shown in outer aspect, and 
the left supraclavicle (s.cl.) seen from within. The lower end 
Fig. 5. — Gyrosteu.s mirahilis, Ag., MS.; left maxilla, outer aspect, one-fourth 
nat. size ; s., anterior symphysial extremity ; .r., palatine process. [Brit. 
Mus., No. P. 3356/.] (From Catal. Foss. Fishes B. M.) 
of the latter (turned downwards in the figure) is produced into 
a considerable rod-like extension. A few remains apparently of 
fin-rays (/) are also observable on the right of the slab. 
The best parasphenoid hitherto discovered is shown of 
one-quarter the natural size in fig. 2. It is imperfect in all 
directions, and especially in front ; but a comparison of the 
parts 23 reserved with the 
parasphenoid of the 
modern sturgeon (fig. 3) 
shows that the two 
bones are essentially 
identical. The posterior 
Fig. 6.— Left maxilla {mx,) and palatine {pi.) of bifurcation and the 
recent sturgeon (Acipemer), outer aspect, . „ i • i p 
much reduced. (From Catal. Foss. Fishes P^"^"' carotid tora- 
B. M.) mina at the base of 
the lateral basipterygoid processes are distinct. 
Numerous specimens of the hyomandibular are known, and 
one of the best and largest in the British Museum is shown 
