129 



the base rather convex ; the mouth large, and the vent 

 circular. The larger areas have two rows of large tubercles 

 next the ambulacra ; between which are two rows of small, 

 surrounded by others still smaller. These tubercles are 

 pierced in their tops, and their surrounding rings are finely 

 crenulated. The ambulacra are bordered, and have three 

 pair of rows of pores in their widest part, which lessen as 

 the space is contracted. The spines are acicular, and are 

 surrounded at their base with a ring, within which is the 

 excavated bulb that articulates with the perforated papillary 

 tubercle. Recent and fossil. — Leske ap. Klein, Tab. 

 xxxvii, fig. 1, 2. 



3. C, papillata. — Orbicular, but the vertex depressed 

 and the base flattish ; the areas with two rows in each of 

 perforated papillae, each surrounded by a circle of granular 

 tubercles and punctured spaces. Between each two winding 

 biporous bands, or ambulacra, a band is raised which cor- 

 responds with the smaller areas : the mouth is nearly round ; 

 the vent varies in its form. Recent and fossil. — Leske 

 ap. Klein, Tab. vii. 



In some fossils, probably of this species, the spines assume 

 a ventricose, clavated form. These have been long known 

 by the name of lapides judaici. 



4. C, atrata. — Ovately hemispherical, rather depressed ; 

 of a violet colour, inclining to black. The tubercles large ; 

 the dorsal spines short, obtuse, and imbricated ; those at the 

 circumference subspathulated. Recent. — Cid. violacea. 

 Leske. 



5. C. crenularis. — Subglobose ; with two rows in the 

 larger areas of large tubercles, crenulated round the pa- 

 pillae. Fossil, from Switzerland. — Bourguet, Petrif. Tab. 

 lii. 344, 347, 348. 



6. C. pseudo-diadema. — Depressedly hemispherical ; the 

 bands straight and biporous ; and two rows of large tubercles 

 in each area. Fossil. 



s. 



