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REPORT OF THE DIRECTOR I9IO 163 



occurring on the latter points. Posterior part of shell with transverse 

 rinkles. Diductor muscles attached to 5 or 6 diverging ridges in 



the pedicle valve; adductor callosities elliptical, deeply depressed on 



cast. 

 Remarks. The sinus and the diductor scars and general form of 



the shell distinguish it from the other species. 



Productus laevicostus White? 



Productus laevicostus White. Journ. Boston Soc. Nat. Hist. 

 7 1220. i860. 



A specimen apparently identical with this species. 



Productus prouti nov. 



Shell small, very arcuate from beak to front, except in old speci- 

 mens when the anterior is nearly straight. Hinge-length slightly 

 exceeding the width of the shell which is nar- 

 row for its height. Surface poorly preserved, 

 but one specimen is marked with 9 or 10 striae 

 to 5 mm. On some of the specimens there 

 is no sinus. 



Dimensions. Length of shell 12 mm; width, 

 14 mm; length of hinge about 16 mm; con- 

 vexity, IO mm. Productus prouti nov. 



Remarks. This species differs from P. Cape ie Trou, Grindstone 1. 

 d o u b 1 e t i in being much more arcuate, more finely striated, and 

 in having a much more highly inflated beak. 



As is shown in the illustration, the shell appears to have had a 

 considerable cardinal area and may possibly have possessed teeth. 

 Better preserved material may show it to be a Productella. 



Productus tenuicostiformis nov. 



Shell subquadrate, gibbous; hinge as long or longer than the 

 transverse diameter of the shell; lateral margins nearly straight from 

 the hinge nearly to the front of the shell where they gently curve 

 into the nearly straight anterior border; beak but slightly produced 

 beyond the hinge, not recurved, very slightly and very broadly 

 inflated. Pedicle valve very strongly arcuate longitudinally and £ 

 terrace is frequently traceable around the shell at the edge of the 

 visceral chamber; surface sculptured with moderately fine radiating 

 striae about equal in width to the intervening depression, increasing 



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