The Hiftory ^ANIMALS, 187 
gibbofity toward the cardo does not give them any very great depth : their furface is 
perfe&ly fmooth, and the colour is a dufky whitifh, without any variegations. 
We have this fpecies in fome of our large rivers, but it is not common: it is abun¬ 
dant in the ditches of Holland. 
Chama gibbofior albida variegata . 
The gibbofe y whitifh , variegated Chama . 
This is about half an inch in breadth, and is nearly as much from the hinge to the 
oppolite verge : the (hells are equally and confiderably deep ; they are (lightly fafciated 
or marked with obfcure, circular lines, at fmall didances 5 the ground colour of the 
(hell is a du(ky whitifh, but it is variegated with olive-coloured fpots. 
We have it in our rivers of Northamptonfhire and Warwickfhire in great abun¬ 
dance ; it is frequent alfo in the rivers of Germany, but there it is more beautiful, 
being frequently variegated with red and green; but the fpecies is dill the fame, 
Chama rotundior fafciata fubrubens . 
The reddifh , round fafciated Chama . 
This is about an inch and a half in diameter, and as much from the hinge to the 
oppolite verge: the (hells are equally hollowed, but not greatly fo; they are lightly 
fafciated, and are of a pale brownifh-red on the outfide, and of a very elegant, pearly 
hue within. 
We have this in fome of our large fifh-ponds, but it is not common with us: I 
have had a great many fpecimens of it from France, fome of them of this reddifh co¬ 
lour, but mod of a pale brown, with little or no red in it. 
Chama fubovata fubecerulea. 
The bluifh , oval Chama . 
This is about half an inch in length from the hinge to the oppolite verge, and is 
fomewhat lefs than that from fide to fide, which is not the ufual cafe with the Chamas: 
it is broad and rounded at the verge, and at the top it runs up fmaller, but terminates 
obtufely ; it is elegantly and finely ftriafed in a longitudinal dire&ion 5 the drke are very 
fine and clofe ; the colour is a pale bluifh-grey. 
We have this in fome of our rivers, but it is not frequent with us. 
The other fpecies of frefh-water Chamse are, 1. The larger, flat, and fmooth 
Chama. 2. The fmaller, flat, and obfcurely fafciated, yellowifh Chama. 3. The 
fmaller, driated, reddi(h, hollowed Chama. 4. The fmall, white, fafciated, gibbofe 
Chama. 5. The great, brown, rough Chama, of a pearly white within. 6. The 
great, olive-coloured, deprefled Chama, with a more even furface. 7. The larger, 
olive-coloured, flat Chama. 
MYTULI, MUSCLES. 
Mytulus tenuifftmus virefcens . 50 \t Qttttl tU 
The extreamly thin , greenijh Mytulus . 
npms is an extreamly elegant (hell: it is near an inch from corner to corner, 
j[ and is about three quarters of an inch from the hinge to the oppolite verge of 
the (hell; it is confiderably gibbofe and deep, and approaches to the figure of the tel- 
lina of authors: the whole furface is lightly fafciated; the colour is a pale, elegant 
green, and the (hell is as thin as the fined paper. 
I met with feveral of this fpecies in the lakes on the mountains in Yorklhire, and 
other parts of the North; we have it from the rivers of France and Germany alfo, 
but it is fo tender and delicate, that it is ufually broke or injured in the carriage 3 it is, 
indeed, hardly poflible it fhould efcape accidents. 
Mytulus 
