EcHiNocYAMus. RADIATA. CATOCYSTI. 481 



Upwards of three inches in diameter ; purple. Oviducts approximatiiif; 

 with the punctured space behind. Vent transversely oval. Inclosed space 

 beneath reniform. Two anterior avenues of pores abbreviated. Primary 

 tubercles, with a central ligament, a moniliform ring at the base, and dis- 

 posed in waved lines. 



EXTINCT SPECIES. 



1. S. cor-miguinum Cordate, subconvex, with five grooves, each with four 



rows in pairs — Echinites cordatus, Lind. 47- t. xii. f. 964. — S. cor. Park. Org. 

 Rem. iii. 28. t. iii. f. 11. — Common in Chalk. 



2. S. rostratus. — Cordiform, dorsal ridge rostrated, anterior part of the shell 

 depressed — Mant. Geol. 192. t. xvii. f. 10-17 — In Chalk. 



3. S. planus — " Ovate, vertex rather depressed ; surface nearly smooth, with 

 eight ? biporous ambulacra, diverging in pairs on each side the back and front, 

 dorsal groove superficial, extending to the mouth ; base slightly convex ; 

 mouth transversely reniform ; vent placed in the upper part of the side." — 

 Mant. Geol. 192. t. xviL f. 9-21 In Chalk. 



CATOCYSTI. 



Gen.V. ECHINOCYAMUS.— Ovoid/margin rounded; ave- 

 nues of pores short and biporous ; mouth and vent adjoin- 

 ing. 



9. E. pusillus. — Body ovate, slightly concave round the 

 mouth, and subdepressed above. 



Spatagus pusillus, Muller, Zool. Dan. iii. p. 18. tab. xci. f. 5, 6. — Echinus 

 ovalis depressus ambulacris quinis, Walker''s Test. Min. p. 25. tab. iii. 

 f. 88. — Ovulum marinum, Iseve, minimum, figura^ compressse, Bor. 

 Com. p. 278. tab. xxviii. f. 26. — Common on all parts of the coast, from 

 Devon to Zetland. 



The margin of the mouth is irregularly notched. Where the avenues 

 meet there are four large pores, the orifices of the oviducts. — Muller states 

 the size at nine lines. I have not found it exceeding two lines, nor ever 

 alive. In some the vertex is prominent, and the avenues of pores indistinct, 

 and they likewise exhibit differences in the disposition of the tubercles. 



Is the " Echinus subrotundus planus lobatus, the flat roundish lobated Echi- 

 nus, the colour opaque, white, from Reculver, very rare," of Walk. Test. 

 Min. 25. t. iii. fig. 89, an Echinocyamus ? I am not aware that it has come 

 under the notice of any recent observer. 



GeN: CONULUS. — Conoid, vent lateral. 



1. C albogaleriis..— Obscurely pentagonal, divided by ten biporous avenues 

 into five large and five very small compartments ; surfaces covered with mi- 

 nute granulse ; vertex with five perforations — Park. Org. Rem iii. 19. t. ii. 

 f. 10, IL— Mant. Geol. 190. t. xvii. f. 8-20— Chalk. 



2. C. vulgaris — Park. Org. Rem. iii. t. ii, f 3 Manl. Geol. 191.— In Chalk. 



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