15 



PRODTTCTUS Martini, 



TAB. CCCXYIL—Ftgs, 2, 3, and 4. 



Spec. Char. Semicylindrical, convex above, 

 with a flattened front, deeply striated, spi- 

 nous ; lesser valve nearly flat, deeply in- 

 serted ; hinge line equal to the width of the 

 shell. 



Syn. Anomites prodiictus. Martm Pet. Derh. 

 tab. 22./. 1, 2, and 3. 



-I- HIS is the Productus spoken of at p. 158 of the first 

 Vol. of this work ; it is distini^uished from every other 

 by the width of its hinge, the neatness of its rather 

 distant stria?, and the great length of its produced 

 front : the ridges between the strife are often furcated 

 upon the front, where also all vestiges of spines ia 

 general disappear : very seldom are spines found in 

 connexion with any part, but the casts shew the roots 

 of spines scattered over the convex surface, and dis- 

 posed in two rows upon each ear : the few spines I have 

 met with are long and pointed. 



Not uncommon in the Derbyshire Limestone. Fig, 4 

 represents a cast in ochracious sandstone, from the river 

 Barn, in Yorkshire ; favoured by Mr. ])anby some years 

 ago. 



Fig. 3 is from a large, very concave, specimen, some- 

 what corrugated, and thus intermediate between P. 

 Martini and the following. 



PKOBUCTUS antiquatus. 



TAB. CCCXYII.— F^^5. 1, 5 and 6. 



Spec. Char. Semicylindrical, short, very con- 

 vex above, longitudinally sulcated and trans- 

 versely corrugated, spinous ; lesser valve 

 nearly flat ; hinge-line shorter than the 

 width of the shell. 



SY^. Annomites semistriatus ? Martin Pet. 

 Derh. tab. 32 and 33. /, 1,2, 3, and 4. 



Distinguished from the last by its less regular stride, 

 and in being corrugated ; the sides near the hinge are 

 particularly rugged ; it is in general also a larger and 

 shorter shell. 



