VOL. XLV.] PHILOSOPHICAL TRANSACTIONS. 43^ 



The above-mentioned gentleman says, the stones are from half a hundred to 

 4 or 5 hundred weight each, lying at all depths to 20 feet under water ; full of 

 cells, each containing a single fish, called by the inhabitants the dottle fish ; 

 which name he judiciously supposes to be a corruption of the word dactylus from 

 their form. He also says, the fish is of the same nature with the common 

 muscle, but much more delicious, and that eating them is never attended with 

 those poisonous symptoms that have been often thought to be caused by eating 

 muscles. 



The shells are indeed in all respects, except one, like the mytulus vulgaris, or 

 common muscle ; these being small at the hinge-end, and having a broad thin 

 edge at the opposite ; whereas the former are nearly equal at both ends, as well 

 as straight and somewhat depressed ; and as to the structure of the fish of both, 

 they are alike, though with this small difference, that the lingula of the com- 

 mon muscle is detached towards the point, and that of the other is confined all 

 along. He therefore submits it, whether either of the following names would 

 not properly express it, viz. mytulus cylindroides, the cylindroid muscle, or my- 

 tulus dactyliformis, the date muscle. Its external fonn conducing much to en- 

 courage the latter, which Mr. More has hinted at, in calling the stone the 

 dottle, dotting, or dating-stone ; for as to the place of its residence, that belongs 

 rather to its general natural history than its distinguishing name. 



Dr. Lister, and after him Mons. D'Argensville, have drawn our pholas with 

 5 shells ; but there is reason to suspect they are only bi-valves ; for on examin- 

 ing those inclosed in the present specimen, in company with Mr. Hill, none of 

 them appeared to have more than 2 shells. And in a specimen of one of these 

 fish, given to Mr. Peter Collinson by Sir Charles Wager, which lodged itself in 

 the bottom of a ship, there were only 2 shells found. Now these ought in like 

 manner, after its generical character, to be ranged among the chamae ; and as 

 they have a proboscis, which none of the mytuli have, he also offers the follow- 

 ing name for this fish, viz. chama longa rugis asperis, alba. The long rough 

 white chama. 



Mr. Baker showed him another species of pholas, which he lately took out of 

 a stone from the coast of Cornwall, and which has more of the pectuncle than 

 any other kind, in its form, cardo, and shutting close ; which the shells just 

 mentioned cannot do : now these 3 distinct kinds of shell-fish can never be said 

 to be rightly called by the single name of pholas. 



The common objection to these fish boring their way into the stones in which 

 they are found, viz. that the stones are first in a soft state, and so harden about 

 them, may be obviated by the following considerations : first, that in Mr. 

 More's great stone, when it was broken, there appeared through its substance 



