70 SPECIES OF THE SYSTEMA. 
Venus meretrix. 
Our author did not possess this species. It appeared in 
both editions of the ‘Systema’ with a precisely similar descrip- 
tion: the only addition in the final one being a reference to the 
details of the ‘Museum Ulrice.’ The illustrative figure in all 
these works was the F of Argenville (pl. 24), which seems to 
me a foreshortened view of the Cytherea lusoria of Chemnitz 
and Lamarck, but was converted into a C. zonaria in the 
corrected edition by Favanne: moreover, it is not unlike the 
meretric of Chemnitz (impudica, Lam.). It was assuredly 
designed for one of these three shells; the second of which, 
with its peculiar colouring and subtrigonal shape, is not so 
suited as the other two to the original diagnosis. The descrip- 
tion in the ‘Museum Ulrice’ is applicable alike to the first or 
third of these three shells, and, probably, also included several 
others. In a case of doubt, like this, it seems expedient to 
continue the name to the shell (Chemn. Conch. Cab. vol. vi. 
pl. 33, f. 347, 348) which has so long borne it, especially 
as the specific individuality of C. lusoria is still a matter of 
uncertainty. 
Venus feta. 
The delineated example (plate 1, fig. 2, 3), which I cannot 
positively refer to any described shell, is marked for this 
species in the Linnean collection, and accurately corresponds 
to its description. The latter being too brief, I hold it 
advisable to somewhat enlarge it. 
C. uma, Lin. (haud auctorum), C. testa tumida, subquadrato- 
rotundata, subobliqua, valde inequilaterali, satis valida, levi- 
gata, nitidiuscula, luted, radiis angustis candidis, subobsoletis 
picta; margine ventrali subarcuato ; dorsali vix convexo, antice 
paullo, postice satis declivi; superficie interna alba, antice et 
postice livido purpurascente fucatéi; lunula magna, ovato- 
cordata, linea tantum circumgceripta, haud retusa; areola nulla ; 
margine interno integerrimo. Long. 1 poll. 
