83 



PRODUCTA fimbriata. 



TAB. CCCCLlX.-^^r 1. 



Spec. Char. Hemispherical, with 6 or 8 trans- 

 verse, crenated, spinous ? furrows ; beak 

 rather produced. 



OOMEWHAT resembling Producta punctata t. 323, but the 

 furrows are more distant, and are crossed by ridges that 

 seem to have been the bases of spines, arranged in the 

 form of a fringe ; the length is greater than the width, 

 and about double the depth ; the lesser valve is concave, 

 with sharper and more numerous, but otherways similar 

 markings, to the larger. 



The specimen lined with Calcareous-spar, from the 

 Limestone of Derbyshire, is preserved in the Collection 

 of Charles Stokes, Esc[. 



PRODUCTA plicatilis. 



TAB. CCCCLIX.—Jig. 2. 



Spec. Char. Transversely oblong, convex 

 above, depressed in the middle, longitudi- 

 nally striated and transversely wrinkled, 

 spinose ; front smooth. 



The transverse rugae are numerous and equal, they only 

 appear upon the upper part of each valve ; the descend- 

 ing front is even and smooth ; the spines are few, 

 scattered over the surface ; the hinge line occupies the 

 whole width of the shell. 



A very neat well defined species rarely found in the 

 Limestone of Derbyshire. We are equally obliged to 

 Mr. Stokes for the opportunity of figuring this, as the 

 preceding specimen. 



