223 
Siphonotreta discoidalis, sp. nov. 
Plate XXL, Figs. 2 and 2a. 
Valves nearly discoidal, excepting at the umbonal region, where they are 
produced into a short beak, below which is a small foramen. Shell surface, 
marked with fine strise, nearly concentric with margin. The specimen from 
which the figure was taken is an impression of the pedicle valve, and the delicate 
surface of the shell is faithfully reproduced in a wax squeeze ; the latter 
shows a distinct trace of the ventral canal. Length of valve 4mm.; width 
4mm. The spines are not preserved in this specimen. 
CHONETES, FISCHER DE WALDHEIM. 
Chonetes concinna, sp. nov. 
Plate XXL, Fig. 3. 
Valves sub-rectangular, with a strong median sulcus on the dorsal side. 
Lateral edges nearly straight, slightly hooked at the posterior angles. Cardinal 
area with a series of strongly developed teeth. Surface of valve finely striate, 
in a nearly vertical manner, near median sinus. Greatest width 6mm. 
This species closely approaches C. minima , Sow., sp.,* in general shape, 
the chief differences being the hooked extremities of the posterior border, 
the finer striations and the stronger median sulcus. 
STROPHOMENA, DE BLAINVILLE. 
Strophomena flabelioides, sp. nov. 
Plate XXI., Fig. 5. 
A cast showing the interior of a dorsal valve of a brachiopod, allied to 
Strophomena, having a median cardinal process and elevated margin. Shell 
plicate, especially around the margin. Length 7mm. 
This form is of somewhat frequent occurrence in the present collection of 
fossils. In the outline of the shell, and in the dichotomous plications of the 
marginal portion of the shell, it reminds us of Orthis flabellulum, but the 
relative form of the valves in our specimen is that of a Strophomena. 
ORTHIS, DALMAN. 
Orthis leviensis (?), Etheridge, fil. f 
Plate XXI., Fig. 4. 
An impression of a ventral valve of an Orthis, which is closely allied to the 
above species, occurs in our series from Heathcote. The drawing was made 
from a wax squeeze, and, allowing for the partial obliteration of the sharp 
ridges, this form closely approaches the specimens found in the Ordovician of 
the Levi Range in South Australia, which were described by Mr. Etheridge, 
junior. Height of the Heathcote specimen 9.5mm.; width 11.5mm. 
Orthis tenera, sp. nov. 
Plate XXL, Figs. 8 and 8a. 
Shell nearly hemispherical, hinge-line straight. Cardinal area only slightly 
elevated. Surface of shell swollen on dorsal side, in the umbonal region. 
Marked by two concentric depressions or bands running nearly parallel with 
the curved border, and numerous fine radial lines from the umbo. Height 8mm.; 
width 13mm. 
* Sil. Syst., 1839, p. 629, PI. XIII., Fig. 4. 
t Pari. Papers, S. Australia, No. 158, 1891, p. 14, PI. I., Figs. 5-7. 
