154 MOLLUSCA FROM THE CRAG. 



3. Cardium nodosulum, S. Wood. Tab. XIII, fig. 3 a — c. 



Cakdium nodosulum. S. Wood. Catalogue, 1810. 



Spec. Char. Testa minutd, subcirculari, parum incequilaterali, compressiusculd, tenui; 

 costatd et nodosa ; costis 30 convexis, papillosis, brevibus, et obtusis. 



Shell small, subcircular, slightly inc([iulatcral, rather compressed, thin, costated, 

 and nodulous ; ribs about 30, convex, and studded with numerous short, obtuse papillae. 



Diameter, Jths of an inch. 



Locality. Red Crag, Sutton. 



Two or three specimens only of this shell are in my cabinet. 



There are several species to which this shell bears considerable resemblance, but to 

 no one does it appear to accord in all its characters ; it must, therefore, remain for the 

 present with the provisional name attached to it in my Catalogue. In form and general 

 outline, it is somewhat like the figure of C.phniulatum, Conrad ; but from the description 

 of that shell by Dr. Gould, ' Invert. Massach.,' p. 91, it has only twenty-si.\ ribs, and 

 an angular ridge on the posterior side, with other characters assigned to nodosum, 

 corresponding precisely in description to that species, and in like manner difi"ering from 

 ours. 



Card, minimum, 'Phil. En. Moll. Sic.,' also resembles it in many characters, but from 

 his description must be distinct, as there appears a great difference in the form of the 

 ribs, for that author speaks of his shell, p. 38, " costis 30 — ^1, planissimis." 



Our shell may be more fully described as nearly equilateral, the posterior side a 

 trifle the larger, very slightly convex, or less tumid than the generality of these small 

 species, somewhat rounded on both sides, rather the less so posteriorly ; the distin- 

 guishing character is in the ribs, which are, at least, 30, not flat, but convex, with 

 a wide space between each, and the centre of these ribs only are covered with short, 

 narrow, obtuse, nodules ; those upon each side, more especially on the posterior, arc 

 smaller than upon the middle of the shell. The interstices between the ribs are broad, 

 deep, concave, and smooth. Card, suecicum has a like number of ribs, but is not 

 smooth between them, is more inequilateral, and has vaulted scales. Card, papillosum, 

 Poli, has a less number of ribs, and is otiicrwise different. 



4. CauDIUM STRIGILLIFERUM, S. Wood. Tab. XIII, fig. .Or/ — d. 



Cardium elong.\tum. S. Wood. Catalogue, KS40. 



Spec. Char. Testa minutd, ovatd, transversa, valde inaquilaterali, tumidd ; costis 24 

 elevatis, planiuscuUs, papilliferis, papillis squamaformibus, sulcis maynis punctatis, vel trans- 

 verse imbricatis. 



Shell small, ovate, transverse, very inequilateral, tumid, with about twenty-four 

 elevated ribs, flattened on the top, and ornamented willi vaulted scales or tubercles ; 

 spaces between the ribs wide, with elevated concentric ridges. 



