151 



SPIRIPER lineatus. 

 TAB. CCCCXCIIL— /g^s. 1 and 2. 



Spec. Char. Gibbose, covered with numerous di- 

 verg-ing sharp striae ; front semicircular, ele- 

 vated in the middle ; from the elevation of the 

 front a convex band proceeds to the beak ; hinge 

 line long and straight ; beaks rather distant. 



The width is nearly double the length ; where the sur- 

 face is perfectly preserved, the elevated striae are found 

 to be minutely granulated; the beaks are curved and 

 approach nearly together, the space between them is 

 rounded, and has a large triangular foramen ; the hinge 

 line does not extend quite the whole width of the shell. 

 Found in the Dudley Limestone. Fig. 2 is from a spe- 

 cimen collected by Charles Stokes, Esq. 



SPIRIPER attenuatus. 



TAB. CCCCXCIII. Jigs. 5, 4 and 5. 



Spec. Char. Convex, covered with numerous linear 

 furrows, which increase in number towards 

 the margin ; front rounded, elevated in the 

 middle, from each side of the elevation a deep 

 furrow proceeds to the beak ; sides produced, 

 pointed ; hinge line long, straight ; space be- 

 tween the beaks flat, with nearly parallel 

 edges. 



The furrows upon the surface of this shell form be- 

 tween them thin branched ribs : in many specimens the 

 elevated part of the front is not followed by a corre- 

 sponding elevation along the surface, although the other 

 valve IS concave in that direction ; the width is nearly 

 three times the length in some specimens, others are 

 less attenuated laterally. 



Produced by the Black Limestone near Dublin. 



