CARBONIFEROUS FOSSILS OF IRELAND. 113 



Producta PECTINOIDES. Phil. 

 Producta pectinoides. Phil. Geol. York. 

 Sp. C/;.— Orbicular, very gibbous; without spines ; radiating ribs broad, smooth, rounded, each divided 

 into three or four, near the margin ; ears short, square. 



Tliis species, and the P. marfjaritacea, should form a subgeneric group ; the structure of their shell is 

 very thin, foliaceous, difiering entirely from that of the other Productai. I have not seen the internal struc- 

 tiu-e. The present species is nearly hemispherical, with short, square ears ; the forking of the nbs near the 

 margin is very remarkable. Length ten lines, width one inch three lines. 



Producta pr^longa. Sow. sp. 



Leptaena prselonga. Sow. Geol. Trans. 



Sp. CA.— Subcylindrical, very gibbous ; mesial furrow shallow ; beak of the dorsal valve large, obtuse ; ears 

 very small ; longitudinal strise strong, unequal. 



This species resembles the P. sctosa, but is distinguished by the coarse, irregular strire, and large, tumid 

 beak ; the front is also more produced than is usual with that species. Length eleven lines, width nine lines. 



Producta pugilis. Phil. 



Producta pugilis. Phil. Geol. York. 



Sp. C/i.— Subcylindrical, quadrangular, front flattened ; sides steep, flattened, parallel; cars small, cylin- 

 drical, acute ; radiating ridges thick, smooth, equal ; a few very large, scattered spines. Breadth of the front 

 equalling its length. 



In general form this resembles the Producta sidcata, but diSers in the unusually large spines, which are 

 very irregularly placed ; the radiating ridges are equal in size, and the surface would be regular were it not that 

 wherever one of the large spines occurs, three or four of the strias become raised, forming a kind of rib from its 

 base to the margin ; this gives the shell an irregularly ribbed^appearance, and frequently conveys the impression 

 of the striffi being unequal in size ; the ears are small and acute, appearing to project from the middle of the flat 

 side ; the mesial hollow is most distinct on the rostral portion of the shell ; the sides of the beak are reticulated 

 by a few concentric wrinkles. Length one inch six lines. 



Producta punctata. Sow. 



Productus punctatus. Sow. Min. Con. — Producta punctata. Phil. Geol. York. 



Sp. Ch. — Shell rounded, wider than long, convex, with a slight mesial depression ; transversely sulcated, 

 the intermediate broad ridges spinulose. 



In this species there are usually about fourteen or fifteen flat, concentric ridges, about a Une and a half in 

 depth ; hispid, with small, cylindrical spines, when these are broken away, as is usually the case, the ridges 

 appear as if punctured mth a pin, whence the specific name. The ventral valve is but slightly concave, with 

 a mesial ridge corresponding to the hollow in the dorsal valve. Length one inch seven lines, width two inches. 



Producta pustuxosa. Phil. 



Producta pustulosa. Phil. Geol. York. 



Sp. Ch. — Rotundato-quadrate, gibbous; beak pointed; a distinct mesial hollow; the entire shell girt 

 with regular, broad, rounded wrinkles, on which the small, oval tubercles are regularly arranged in transverse 

 rows, except on the ears, where the wrinkles are smooth. 



2F 



