Clypeus. 
RADIATA. ANOCYSTI. 
479 
Avenues of the pores nearly smooth, and narrower than the preceding. 
The double row of primary tubercles in each compartment very .distinct, the 
smaller ones few in number, having a space in tho middle of each, nearly 
smooth. 
* Five double rows of pores in each avenue. The ring round 
the vent formed by the plates of the pelvis and the costals. 
4. E. subangularis, — Each oblique row of pores curved to- 
wards the mouth, the intervening spaces with a row of tuber- 
cles. 
Cidaris subangularis, Leske, p. 106. t. iii. C, D.— Common on the rocks 
with E. escidentus. 
In each of the large compartments there are about ten tubercles in each 
transverse row, and in the smaller about six. Each plate, however, has one 
tubercle larger than the rest. The margin of each pair of pores seems raised, 
with a groove between those which are contiguous in the same row. The 
markings on the avenues of pores appear to distinguish this species from the 
Rupestris of Leske, p. 111., which is the Saxatilis of Gmelin. It is probable 
that this species has been confounded with E. esculentus. The structure of 
the pelvis, and the number of pores, characters belonging to different sys- 
tems of organs in the animal, leave no room to doubt of the propriety of their 
separation. 
EJtTINCT SPECIES. 
1. E. saxatilis. — Hemispherical, depressed ; compartments with two rows of 
small, nearly equal tubercles ; little more than half an inch in diameter.— 
Park. Org. Rem. iii. t. iii. f. 1 — Mant. Geol. \^d.—~Chalk. 
2. E. Konigii. — Circular, much depressed, lesser compartments with two 
rows of tubercles ; thirty rows of tubercles on the vertex, and twenty on the 
base.— ParA:. Org. Rem. iii. 12. t. i. f. 10. — Mant. Geol. 189. — Chalk. 
Gen. clypeus. — D epressed, with ten avenues of pores in 
pairs ; a groove from the vertex to the margin on one side. 
1. C. sinuatus. — Round, the avenues of pores, in the pairs, recede from each 
other from the vortex towards the margin — (P/o^, t. ii. f. 9, 10.) — List. An. 
Ang. 224. — Park. Org. Rem. ii. t. ii. f. 1. — Oolite. 
2. C. hiatus. — The groove deep, and dividing the margin into two lobes.— 
List. An. Ang. 223 — Oolite. 
3. C. clunicularis.’^0'V2iy.’-~{S'mith'’s Fossils, f. 6.), Geol. Eng. 188. — Oolite. 
PLEUROCYSTI. 
Gen. III. ECHINARACHNIUS.— Mouth central. 
5. Fa. placenta. — Subconic, with five avenues of pores, cir- 
cumference angular, base flat. 
Echinus p. Linn. Syst. mcv. 16.— ‘‘Isle of Foulah, very rare,” Professor 
Jameson. 
