184 
more robust, the aperture more dilated, and the strise mucb more 
crowded, Lamarck and others say that they may be distinguished 
by the rectilinear beak of the antiquus. This also is a good char- 
acter, but in my cabinet is a large and fine specimen of the latter, 
of which the beak is as much recurved as in the present species. 
PI. 29 ; upper and lower figures. 
Fusus ciNEREUS. — Specific character. With elevated costse j 
and transverse, filiform lines. 
Fusus cinereuSy nob. Journ. Acad. Nat. Sci.j vol. 2, p. 236. 
Ohs. — This species is common in the estuaries of the eastern 
shores of Maryland and New Jersey. It has considerable resem- 
blance to two figures in Listens Hist. Conch, pi. 924, f. 16, 6, and 
pi. 939, f. 34, a. The first of which is considered an uncertain 
figure, and the latter is said by Dillwyn to be the undatus^ and is 
interrogatively referred to by Lamarck. Our shell certainly ap- 
proaches the genus Purpura in habit, but it cannot enter with 
Lamarck’s characters. PI. 29 ; two middle figures. 
Paludina. — Ohs. This genus may be distinguished from 
Melania by the construction of the operculum, which has no other 
than concentric lines of growth, whilst that of ' Melania has the 
lines of accretion spirally radiate. 
The name of the genus was adopted by Lamark from Bruguiere, 
but Montfort applied to it the name of Viviparu^, which is re- 
tained by Blainville in his plate, though in the text he adopts 
that of Paludina. 
Paludina PONDEROSA.-->§>ec^y^c character. Shell thick; 
labrum more prominent towards the base. 
Paludina ponderosa^ noh. Journ. Acad. Nat. Sci. vol. 2, j?. 
173. 
05s.— This shell is common in many parts of the Ohio as well 
as its tributaries. In its full grown state it is very thick and pon. 
derous, enlarging so much in its body whorl, as to appear very 
different from the young shell. In the early stages of growth it 
resembles P. decisa^ nob., from which indeed the back view would 
hardly distinguish it ; but a sufficiently distinctive character re- 
sides in the lower part of the labium, which in the decisa is not 
obviously produced, whereas, in the present species it is consider- 
ably advanced, as in many species of Melania^ to which genus it 
is closely related. PI. 30, fig. 1 
