Miscellanea. 321 



finer striae ; and from both it differs in the form of its muscular 

 impressions. Length 7 lines, width /-j lines. 



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

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

 Sp. Char. Longitudinally obovate, gently convex ; length of ventral 

 valve tw^o-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 convex ; 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 con- 

 centric imbrications of growth, between each pair of the primary 

 ones as they approach the margin, beyond which, when well 

 preserved, thej^ 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 undis- 

 tinguishable from the British carboniferous specimens. 



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



Productus hracliyth(Brus (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 Hull's quarry, 

 Hobart Town : associated with this there is abundance of a flatter 

 species, concentrically wrinkled and with more irregularly placed, 

 blunt, round spines, which may, or may not, be distinct from 

 the P. fragaria and P. caperata of the upper Devonian and lower 

 Irish carboniferous shales ; but from the state of preservation I 

 cannot satisfy myself of the species. 



Productus undulatus (M'Coy). PI. XIII. fig. 2. 

 Sp. Char. Subquadrangular, one-third wider than long, gibbose, 

 front slightly concave at the margin ; sides nearly rectangular, 

 obtusely rounded ; beak large, tumid ; surface with fine, close, 

 short, undulating transverse wrinkles; a few obscure traces of 

 oblong spines towards the margin. 



