478 
RADIATA. ANOCYSTI. 
Echinus. 
tween the pores, consist each of a large and small tubercle, supporting small 
spines, and scattered eminences to which the articulated bodies adhere, and 
two pores. The five bones of the pelvis are subquadrangular, from the ring 
of the vent, and, externally, are wedged in by fine subl^iangular costse. 
EXTINCT SPECIES. 
1. C. ParJcinsonL — The tubercles immediately above the margin the lar. 
gest ; the small compartments prominent. — Park. Org. Rem. iii. 10. t. i. f. 4, 
6-8. — Lower Oolite. 
2. C. papillata. — Body depressed; each compartments with two rows of 
tubercles, encircled by a distinct groove at the base. — Park. Org. Rem. iii. 
t. 1. f. 9. — Mant. Geol. 189. t. xvii. £ 18. — In Chalk and Oolite. 
3. C. Lesser compartments half the width of the larger ones ; 
tubercles crenulated at the base. — Echinita, Park. Org. Rem. iii. 13. t. i. f. 6. 
.^Oolite. 
4. C. t/rie.— Single plates only observed ; tubercle with a double ring, the 
margin of the plate granulated; spines finely striated longitudinally, and 
prickly towards the extremity. I have found, adjacent, what appears to be 
one of the teeth, — Echinus, CTire, Ruth. 318. t. xvi. f. 8. — Carhoniferms 
Limestone. 
Many more species are indistinctly referred to by Plott, Lister, Luid, and 
Parkinson. 
Gen. II. ECHINUS. Sea-Urchin. — Tubercles and spines 
destitute of the central connecting ligament. 
In this genus the primary spines are more numerous, and 
produced ; the avenues of pores are separated by larger 
tubercular spaces, approaching at each end. 
* Three double rows of pores in each avenue ; the ring round 
the vent formed by the plates of the pelvis. 
% E. esculentus. — Plates covered with numerous nearly equal 
tubercles. 
Merret’s Pin. 192. List. An. Ang. 169. tab. iii. f. 18. Sih. Scot. ii. 3* 
p. 26*— jSorZ. Corn. p. 278. tab. xxviii. 27. Monro., Phys. P’ishes, p. 66* 
tab. xliii. and xliv. Perm. Br. Zool. iv. p. 67. tab. xxxiv. f. 74. Cor- 
diner"* s Ruins, No. xiii — Found on rocks at low tides, common. 
This species varies considerably in shape and colour. The avenues of the 
pores have waved transverse grooves, and a few scattered tubercles. In each 
compartment there are two rows of primary tubercles, with numerous others, 
of different sizes, covering the whole surface. A series of 10 tuberculated 
plates surrounding the margin of the mouth, each with a central extensile 
sucker. 
3. E. miliaris. — Plates with a single large, and a few small, 
tubercles. 
Cidaris miliaris saxatilis, Leske ap. Klun. p. 82. tab. ii. A, B, C, D. xxxi, 
A, D. xxxviii. 2, 3 — E. m. Flem. Mem. Wern.ii. p. 246.— .From Zet- 
land, in deep water. 
