686 APPENDIXI 
centric lines of growth.—Height 4 inch; length 35, H.—Plate 2, fig. 6, a, inner view 
of a valve; 6, a worn specimen of shell with one valve broken through. 
Black Head, District of Illawarra. 
Approaches the Lingula lata of Murchison, (Silurian System, pl. 8, fig. 11,) but it is 
not at all ‘¢ squarish.” 
Lingula ovata, Exped. Foss., Amer. Jour. Sci., i. Ser., iv. 152. 
13. Propuctus rraciiis (Danaz).—Subquadrate, tumid, laterally and in front abrupt, 
a little longer than high. Cardinal margin straight, about as long as breadth of shell. 
Beak small, not inflexed. Surface very finely and irregularly striate, with some con- 
centric undulations.—Height 14 inches; length 1,5; H.; thickness between the valves 
about ,4°, H.—Plate 2, fig. 7, a, b, c, different views, natural size ; d, profile of section. 
Wollongong Point, Illawarra. 
This species differs from the brachytherus in its much less prominent beak, and its 
longer hinge line. 
Productus fragilis, Exped. Foss., in Amer. Jour. Sci., ii. Ser., iv. 153. 
14. Propuctus BRAcHYTHERUS (G. Sowerby).—Plate 2, fig. 8. 
Wollongong Point, Illawarra. 
A large number of specimens of this species were found clustered together in the Wol- 
longong sandstone. ‘The rudiments of spines are quite distinct. 
Productus brachytherus, G. Sowerby, Darwin’s Volcanic Islands, p. 158. 
—————_—_—_—_—_—_—__, J. Morris, Strzelecki, op. cit., p. 284, pl. 14, fig. 4, a, b, ¢. 
b. Mollusca Acephala. 
15. Sorecurtus (!) rLyrpricus (Dana).—Scarcely at all convex ; oblong and neatly 
elliptical, with no beak; length twice the breadth, and anterior part half the posterior. 
Surface smooth, with obsolete striae of growth. Supero-anterior margin slightly de- 
pressed. Teeth of the hinge obsolete——Length 1:4 inches.—Plate 2, fig. 9; an exterior 
cast, natural size. 
Wollongong Point, Illawarra. 
It is difficult to determine whether this and the following species are true Solecurti or 
not. ‘The hinge, of which we have a good cast in the specimen, shows no appearance of 
teeth. There is a delicate line extending from the point of the hinge obliquely back- 
ward, but whether it arises from a fracture, or a slender rib on the surface, it is difficult 
to determine. It shows nearly alike on both the exterior and interior casts, and appears 
rather to be a peculiarity of the shell itself. No palleal or muscular impressions are 
visible. 
Solen (Solecurtus 2) elhpticus, Exped. Fossils, Amer. Jour. Sci., ii. Ser., iv. 153. 
16, Sotecurtus (PsamMostia 1) pLANULATUS (Dana).—Height rather less than half the 
length ; superior and inferior margins nearly straight. Valves nearly flat, with a slight 
