The Uiflory ANIMALS. 197 
Thus much of the general ftru&ure of the creature may ferve alfo as part of the 
deferiptions of the fucceeaing fpecies, for they all agree in general in thefe particulars. 
This fpecies is frequent in our feas, and in moft of the other parts of Europe 3 it 
becomes white, by long lying on the fhore. 
%■ 
Centronia fuhglohofa fpinis maximis quadratis. 
The roundifo Centronia , with very large, fquare jVines . 
This is an extreamly lingular fpecies, and, when perfect, makes a very odd figure 3 
but the fpines are fo eafily difplaced, that we very rarely meet with it fo: the body or 
fhell, exclufively of the fpines, is about two inches in diameter, and as much in 
height, but, with thofe appendages on it, meafures nearly three times as much • it has 
a large aperture at the bafe, where the mouth is placed, and a fmaller at the fummit, 
both of a roundilh but fomewhat dentated figure: the whole furface of the fhell is befet 
with large tubercles or papillae, though they are much lefs numerous than in thofe which 
have them fmaller: on thefe are affixed the fpines5 they are an inch and a half in 
length, and nearly a third of an inch in diameter in the largefh part: they are largeft 
near the middle, and have four angles, which give them a fquare figure at the bafe, 
where they are affixed to the papillae of the fhell3 they have a kind of head, formed fo 
as to fit the papilla f at the other end they are obtufe : the colour of the body of the 
fhell is a deep brown 3 the fpines are of a paler brown, fomewhat approaching to 
whitifh. 
We have it from the coafis of the American illands, but it is very rare even there, 
and is feldom taken up without the lofs of many of it’s fpines; and the greater part of 
the reft are ufually loft, before it comes to us 3 fo that we ufually meet With only the 
body of the fhell, with a loofe fpine or two that have fallen off from it. 
1 1 
Centronia fuhglohofa fpinis maximis cylindraceis . 
The roundifh Centronia , with very large , rounded fpines . 
This is an extreamly elegant fpecies 3 the body of the fhell, which is all we ufually 
meet with, is of a figure approaching to roundifh, but much depreffed at the bafe : it 
has a large opening at the center of the bafe, and a fmaller on the fummit, both 
approaching to a rounded figure, but with dentated edges: the papilke on this fpecies 
are but few in number, but they are extreamly beautiful 3 they are of the breadth of a 
filver two-pence, and are of a figure approaching to that of a fegment of a fphere 3 at 
their top there ftands a little obtufe umbo, and round about the verge of each there is a 
circle of little round protuberances: thefe papillae are placed in double feries, each fe- 
ries having about ten of them 3 and thefe are feparated by broad, undulated fa fog? or 
bands, running from the upper orifice of the fhell to the lower: the colour of the fhell 
is a faint red, when recent 3 but we ufually meet with it white, from it’s having 
lain long on the fliores. This is all we ufually fee of this fpecies in our cabinets 3 but^ 
when the creature is perfect and living, there is affixed to each of thefe papilla? a fpine 
of two inches in length, and of the thicknefs of a child’s finger 3 thefe have a kind of 
head at one end, where they have been fixed to the papilla, and at the other fliey are 
obtufe 3 they are of a rounded, not angulated, figure, and are nearly of the fame thick¬ 
nefs all the way, only a little largeft toward the middle. 
This is a native of the Red-Sea and of the Perfian Gulph; the fineft we have feen 
have been taken up about the fliores of the ifland of Ormus. 
Centronia fuhglohofa fpinis variisfuhecerulea. 
The roundifh, bluifo Centronia , with differently fkaped fpines . 
i his is alio a very elegant fpecies : the body is of a roundifh figure, but flatted at 
the bafe, and the aperture at the top is very large, nearly equal to that at the bafe in 
diame^i . the whoie furface is very elegantly diverfified with papilla? of various forms 
ana fizes; theie are divined into certain feries by five longitudinal fafeis, which are ele¬ 
gantly formed, and are full of little perforations 3 between thefe there ftand feveral fe¬ 
ries of larger and of fmaller papillae-, all following the direction of the bands, and all 
very regularly arranged : this is all that we ufually fee of this fpecies in our cabinets, 
E e e but. 
