C 429 ] 
are great variety of fpecies of this animal, fo thefe 
fpecies differ from each other in their form. The 
bodies of lome of them are hemifpherical, others cy- 
lindrical, and others (h aped like a fig. Their fub- 
ftance likewife differs ; for fome are "(tiff and gela- 
tinous, others flefihy and rrmfcular ; but they are all 
capable of altering their fhape, when they extend 
their bodies and claws in fearch of their food. We 
find them on our rocky coafts at low water, fixed in 
the (hallows to fome folid fubdance, by a broad 
bafe like a fucker; but they can fhift their fit ifation, 
though their movement is very flow. 
They have only one opening, which is in the 
center of the uppermoft part of the animal ; round 
this aie placed rows of flefliy claws ; this opening is 
the mouth of the animal, and is capable of great 
extenfion : it is amazing to fee what large (hell fi(h 
fome of them can fwallow, fuch as mufcles, crabs, 
&c. when it has fucked out the fifli, it throws back 
the (hells through the fame paffage. Through this 
opening it likewife produces its young ones alive, 
already furniflied with little claws ; which, as foon 
as they fix tnemfelves, they begin to extend in fearch 
of food. 
They are found all round the coafis of England ; 
but the coafts of Suliex and Cornwall furnifh us 
with the greateft varieties of them. The ifiands in 
the Wed Indies are likewife remarkable for many 
kinds of them, as appear from the different forts 
fent to your Lordfhip by Mr. Greg. 
Do&or Gaertner, F. R. S. who has deferibed four 
fpecies of the Englifh ones in. the Phil. Trank * fays 
* Vide Phil. Tranf. Vol. LJL p. 75. Tab. I. fig. 1, 2, 4, 
and 5 ; the animal in fig. 3, in the lame Plate is ranked in 
I they 
