ECH 
late., all of them bifarioufly tuberculate : avenues exca¬ 
vated and bifarioufly porous. Found at Verona in a pe¬ 
trified (late ; grey-yellow. 
9. Echinus globulus: hemifpherical, fiubglobujar, 
with ten avenues, the (paces muricate at the (ides and 
porous in the middle. Inhabits the Indian Ocean. 
10. Echinus fphasroides: hemifpherical, gibbous: 
avenues ten, every where muricate and porous in the mid¬ 
dle. Found in the Indian Ocean. 
11. Echinus gratilla: hemifpherical, gibbous ; ave¬ 
nues ten, triplicate ; the fpaces muricate in a deculfate 
form. Inhabits the Indian Ocean. 
12. Echinus lixula : hemifpherical, with ten avenues 
in approximate pairs; the fpaces tranfverfely muricate 
and punctured. Inhabits the Indian Ocean. 
13. Echinus faxatilis: hemifpherical, deprefled ; pores 
of the avenues in a curved line, the curves oblique at 
the bafe. Inhabits the Mediterranean and Indian Seas. 
Shell fub elliptic, violet-grey or white ; protuberances vio¬ 
let, reddilh or yellowifli, in two or three iongitudinal rows; 
pores of the avenues double, five pair in a row ; mouth 
large ; vent furrounded with ovate acute feutes; fpines 
rigid, reddilh-brown, with violet tips. This fomewhat 
xefembles the mamillatvs, and is equally good food. The 
fpines are long, fmooth, folid, fpear-fluped, of a brownifii 
colour, and give a metallic found when they fall. In the 
middle appears the mouth, armed with its teeth, which 
are five triangular bones, hollow, and bent ; their points 
unite outfide the Ihell, and form a cone ; their broad ex¬ 
tremities are within, placed circularly. This is exhibited 
in the engraving at fig. 4. 
14. Echinus feneftratus : orbicular, with a fiat fene- 
ftrate bale ; fpaces ten, with unequal final 1 and large tu¬ 
bercles ; mouth with ten angles. Shell white, with gra¬ 
nulations over all the fpaces and avenues; in the larger 
fpaces are fix rows of warts refembling papillae ; avenues 
broad, with three pair of pores and two towards the 
crown ; fpines violet-black ; vent pentangular. 
15. Echinus fubangularis: hemifpherical, orbicular, 
with ten fpaces; the lefler ones elevated, and ten rows 
of tubercles in each. Shell greenifh-afh, a little inclin¬ 
ing to chefnut, and pulvinate at the bale ; fpaces with 
four tubercles placed in a rhombic form: pores of the 
avenues curved, in four or five pairs. 
16. Echinus ovaritis: ovate; the larger fpaces bifa¬ 
rioufly tuberculate. Found in a petrified Hate in Eng¬ 
land and Normandy. 
17. Echinus diadema, or little turban. Hemifpherical, 
deprefled, with five avenues longitudinally tuberculate; 
the fpaces lanceolate. It varies, 1. With tuberculate 
bands. 2. Greenifli-yellow. 3. Blackifh, variolous, 
with long fpines. 4. Spines black, annulate with white. 
This fpecies inhabits the fands of the Indian Ocean. 
Shell orbicular, with a deprefled top, rich blue or grey- 
blue ; mouth large ; vent circular and furrounded with a 
pentangular fkin ; fpaces bifarioufly tuberculate, the tu¬ 
bercles perforated at the tip ; avenues with three pair of 
pores at the bafe and one at the tip ; fpines violet and 
blue-grey. This deferves notice in preference to feverai 
others, from the regularity of its ftrufture, and the circu¬ 
lar arrangement of its fpines, as fltewn at fig. 5, in the en¬ 
graving. It has been obferved that the fhell of the fea- 
urchin, before it is cleaned, is covered with a tender fkin ; 
this probably enables the animal to unite and (Irengthen 
its brittle Ihell, which confifls of fo many difiiwSt pieces. 
Yet this (kin may be foftened in warm rain-water, fo as to 
be removed by a bruth ; and the (hell, being then ex- 
pofed to the fun, becomes white, only the ten Angle or 
five double lines remaining black. 
j8. Echinus calamarius : lpheroid,. deprefled ; ave¬ 
nues five, with black porous margins, granulate in the 
middle with a double row of larger prominent dots. In. 
habits-the Indian Sea : greenifli-white. Smaller tubercles 
with green very brittle bridles; fpines refembling the 
Voh, VI, No, 345. 
I N U S. 229 
Hem of the equifetum, whitifli annulate with green and 
grey at the tip. 
19. Echinus aranelformis: orbicular, grey, with pur. 
pie-grey fpines thicker in the middle. Inhabits the Ame¬ 
rican feas. 
20. Echinus flellatus : with the lower fpines capillary ; 
likewife found in the American feas. 
21. Echinus radiatus : with five radiate avenues, forked 
at the tip. Each of the avenues is terminated by two 
vvhitifli rays, and perforated with pale red foramina, 
22. Echinus circinatus : with ten granulate fpaces, bi¬ 
farioufly tuberculate; the larger ones excavated, the lefs 
ones elevated, and fubpulvinate at the bafe. Found hi¬ 
therto only among the foflile echini. 
23. Echinus cidaris, or great turban: hemifpherical, 
deprefled, with five flexuous linear avenues, the fpaces 
alternately bifarious. Its varieties are, i.'Ofa fmaller 
fize. 2. With the fpines fufiform. 3. With the fpines 
claviculate. 4. With the fpines obtufe. This fpecies 
inhabits the Indian Ocean, generally of a livid-grey co¬ 
lour and flat at the bafe; fpaces granulate; with two 
rows of protuberances placed alternately, furnifhed with 
perforated papillae, furrounded with a circle or two of 
granulations, and Teparated by a groove running round 
them ; in the place of fmaller ones is an eminent band be¬ 
tween the avenues; mouth rather large. The tubercles are 
pretty large, regularly placed in five double rows ; be¬ 
tween each double row' runs a thick line fomewhat waved, 
which diflinftly (hows the five compartments of the whole 
(hell, each of which contains two rows of tubercles ; and 
each tubercle (lands upon a white nipple, inclofed in a 
railed granulated border. The two rows of tubercles on 
each divilion go from the vent to the mouth, but not in 
ftrait or parallel lines ; they run rather oblique and alter¬ 
nate, i. e. the tubercle in one line Hands oppofite to the 
(pace in the other. By the fide of each double row of 
tubercles runs a waved broad flripe perforated with ob¬ 
long holes ; and thefe ftripes divide the (hell into five 
lobes. The tubercles look like buttons, and are of a yel- 
lovvifh colour; in the centre of each may be obferved the 
orifice through which the tendon pafles which fallens the 
(pine to the (hell or body. The fpines are very large, 
and ciub-fhaped ; but they are of different fizes according 
to the fize of the animal. A cidaris or turban with its 
fpines complete is now confidered as a great curiofity. 
The variety of the cidaris with fufiform lpines is never- 
thelefs the mod rare and beautiful of this family. The 
fpines are large and fwelled at the bafe, but grow (mail to¬ 
wards the top, which is terminated with a rim; and there 
are longitudinal Arise upon each, made up of raifed dots, 
fo that they have the appearance of being notched. Sixty 
of thefe have been counted upon one fea-urchin, without 
reckoning the young ones that might afterwards pufli 
forth. Each (pine (kinds in the midfl of a circle confid¬ 
ing of about twenty little white leaves riling up taper 
like a crown, concealing and firengthening the bafe of 
the fpine ; and between the rows of fpines there is a 
double row of thefe leaves, direfted oppofite ways to 
fupport each row of fpines. The anus is at the apex, 
and round it are five fpines placed pentagonally; the 
mouth is at bottom, and included in a double row of ten 
fhort fpines. All the reft of the fpines are long. This 
fpecies is often found petrified; but feldom in its natural 
(fate, fince it inhabits the inacceflible depths of the fea. 
One of thefe is reprefented in the preceding engraving at 
fig.6; and one of the triangular fpines of the claviculate 
fpecies, at c. The ihell alfo of the claviculate cidaris, 
without the fpines, is exhibited in the Echinus Plate II. 
fig. j, to (hew its tubercles, ftripes, and perforations. 
Another variety of the cidaris, remarkable for the An¬ 
gularity and length of the (pines, is referred by Knorr to 
this fpecies. Its tubercles'are placed upon nipples, like 
the cidaris, or great turban. This is fometimes called 
the little turban, (though it be the fize of two fifts,) be- 
3 N catifg 
