SEMIOXOTTD.E. 
67 
trunk and smaller head. Dorsal fin considerably longer than the 
anal and not remarkably elevated. 
Form. <Sf Log. Lower Hawkesbury-Wianamatta Series (Upper 
Trias): Gosford, New South Wales. 
P. 6274. Two imperfect fishes. By exchange , 1890. 
Pristisomns erassus, A. S. Woodward. 
1890. Pristisomus crassus , A. S. Woodward, op. cit. p. 36, pi. v. 
figs. 5-7. 
Type. Nearly complete fish: Geol. Survey Museum, Sydney. 
A species about as large as the foregoing, but with more robust 
and less deepened trunk. Head with opercular apparatus occupying 
at least one-quarter of the total length; maximum depth of trunk 
contained about three times in the total length of the fish. Dorsal 
fin considerably larger than the anal, as long as deep. 
Form. Sf Log. Lower Hawkesbury-Wianamatta Series (Upper 
Trias): Gosford, New South Wales. 
P. 6276. Trunk showing dorsal and part of caudal fin. 
By exchange , 1890. 
P. 6277. Slab with nearly complete fish, associated with P. gracilis. 
By exchange , 1890. 
Genus SARGOBOBJ* Plieninger. 
[Wiirtt. Jahresh. vol. iii. 1847, p. 165.] 
An indefinable genus known only by the external incisive teeth. 
The dental crown is sharply separated from the long, cylindrical or 
nearly quadrangular root, and is chisel-like in shape. 
It seems probable that the fish possessing such teeth would also 
have tritoral teeth on the inner bones of the mouth. As originally 
suggested by Plieninger, it is, therefore, not unlikely that the small 
Bhsetic teeth named Psa mmodus orbi cularis (Meyer & Plieninger, 
Beitr. Pal. 
ascribed to 
by Agassiz, Poiss. Loss. vol. ii. pt. ii. 1844, pp. 216, 300), truly 
belong to Sargodon. Similar tritoral teeth have been described from 
the Bhsetic of Leicestershire (A. S. Woodward, Trans. Leicester Lit. 
& Phil. Soc., n. s. vol. i. pt. xi. 1889, p. 20), Somersetshire, and 
Gloucestershire (M. Browne, Bep. Brit. Assoc. 1891, p. 645), and 
some are preserved in the Collection from Aust Cliff, near Bristol 
(P. 6069 a. Presented by F. Harford , Esq., 1889). 
e 2 
Wiirttembergs, 1844, p. 117, pi. x. fig. 24), and others 
Sp hcerodus minimu s (ibid. p. 117, pi. x. fig. 23, named 
