of the Rocks associated with the Coal of Australia. 235 



lineata, and to the carboniferous O. Michelini (Lev.), (O.filiaria, 

 Phil.). From the former it is distinguished by its narrow, lon- 

 gitudinally obovate figure, and from the latter by its wider hinge- 

 line and much finer striae ; and from both it differs in the form 

 of its muscular impressions. Length 7 lines, width 7^ lines. 

 Abundant in the shales of Lewin's Brook, N. S.Wales. 



Orthis spinigera (M'Coy). PI. XIII. fig. 3. 



Sp. Char. Longitudinally obovate, gentry convex ; length of ven- 

 tral valve two- thirds the width, width greatest near the front 

 margin, narrowing rapidly towards the hinge-line, the length 

 of which is little more than half the width towards the front ; 

 cardinal area triangular, flat, half as high as wide ; sides of the 

 shell much rounded ; front margin without sinus, slightly con- 

 vex; surface with two or three strong distant imbrications of 

 growth, crossed by numerous small, strong, angular, radiating 

 ridges (about twenty-two at two lines from the beak) ; they are 

 nearly equal in thickness, but shorter ones are interpolated, 

 chiefly at the concentric imbrications of growth, between each 

 pair of the primary ones as they approach the margin, beyond 

 which, when well preserved, they are produced into slender 

 conical spines ; they are about their own diameter apart, the 

 intervening flat spaces being coarsely striated across. 

 Somewhat allied to the Russian O. plana (Pand. sp.), but very 

 distinct by the character of the striation and by the short hinge- 

 line and comparative width of the front. Length of ventral valve 

 5 lines, width 7 lines ; height of cardinal area 2 lines, width of 

 hinge-line 4 lines. 



Rare in the shale of Dunvegan, N. S. Wales. 



Productus antiquatus (Sow.). 

 Reticulated rostral portions well preserved and perfectly un- 

 distinguishable from the British carboniferous specimens. 

 Common in the hard schist of Lewin's Brook, N. S. Wales. 



Productus brachythcerus (Sow.). 

 Very common in the calcareous grit of Loder's Creek, and also 

 at Korinda, N. S. Wales. 



Productus setosus (Phil.). 

 I find the Australian species undistinguishable when minutely 

 compared with our common British mountain limestone species 

 above-named. In the dark indurated schist of Lewin's Brook, 

 N. S. Wales. 



Productus scabriculus (Sow.). 



In the calcareous flags and dark limestone of Hall's quarry, 



17* 



