GASTROPODA (SCUTIBRANCHIA. 
Ill 
NERITIDiE. 
Neritopsis radula (L.). The operculum provided with a peculiar 
appendage, described by H. Crosse [cf. Zool. Rec. xi. p. 147] ; he confirms 
Beaudouin’s supposition that Peltarion (Eudes) is founded on the oper- 
culum of a fossil species of Neritopsis ; J. de Conch, xxiii. pp. 57-66, 
pi. iv. fig. S, and pi. ii. fig. 4. P. Fischer also has examined the anatomy 
of this species ; it proves to be allied to Nerita ; the radula is decidedly 
rhipidoglossate, and analogous to that of the Neritidce, but the central 
and the first lateral teeth are wanting ; tom. cit. pp. 197 & 204, pi. xi. 
The only known species figured in Reeve’s Conchologia Iconica, part 
322. 
Neritina. A monograph is commenced by E. v. Martens in Kiister’s 
Conch. Cab. pt. 243, a general introduction gives the conchological and 
anatomical peculiarities of this genus, which can be distinguished from 
Nerita (L.) only by slight differences in the operculum and by the 
general facies. It is divided into the sub-genera : — AmYona (Martens, 
1869), Neritcea (Roth.), with several sub-divisions, Neritodryas (Martens), 
Clithon (Montf.), Theodoxus (Montf.), and Neritilia, subg. n., chiefiy on 
account of peculiarities in the appendages of the operculum, though 
the differences in the radula also are compared. 30 species belonging 
to the first two sub -genera are described and figured, the following 
being new : — N. ruhicunda, p. 32, pi. vi. figs. 20-23, Borneo ; conglohata^ 
p. 57, pi. viii. figs. 7-9, Celebes ; cryptospira^ p. 61, pi. viii. figs. 10-12, 
Labuan; (Martens, 1860), not before figured, p. 54, pi. ix. 
figs. 18 & 19, Japan. The geographical occurrence is pointed out as fully 
as possible in each species. 
Neritina hnorri (Reel.) [iris, Mouss.], hechi (Reel.) [cryptospiral, 
picta (Sow.), lahiosa (Sow.)*, reclivata (Say), zebra (Brug.) [communis'], 
cumingiana (Brod.), semiconica (Lam.), turrita (Chemn.), sumatr'ensis 
(Sow.), dubia (Chemn.), gagates (Lam.) [cornea, L.J, fiuviatilis (L.), 
antiquata (Kiist.), prevostiana (Partsch), bellardi (Mouss.), velascoi, 
(Graells), (L.), salonitana (Kiist.), stragulata (Menke), dalmatina 
{Z\Qg\.'), pustulosa (Parr.), and belladonna (Psixv.) ', radula described by 
Troschel, Gebiss d. Schnecken, ii. p. 176-180, most of them, and also N. 
virginea (L.), transversalis (Ziegl.), viridis (L.), jordani (Sow.), and 
crepidularia (Lam.), figured, pi. xvi. figs. 7-18. The author comes to the 
conclusion that of these only N. viridis (L.) by its radula justifies the 
use of a distinct genus, Smaragdia (Issel) ; the others indeed exhibit 
some differences (the hood edge and the edge of the marginal teeth being 
in some entire, and in others denticulated), but it is not possible to form 
natural groups by these characters ; 1. c. p. 173. [The Recorder has 
examined some of the shells, out of which Prof. Troschel took the radula 
which he describes and figures, and has recognized that some were 
wrongly named, as shown by the corrections above. Species of Neritina 
are often wrongly named in collections, and this is very prejudicial to thp 
general understanding of their natural groups.] 
Neritina maroccana, Paladilhe, R. Z. (3) iii. p. 93, pi. ix. figs. 26-28, 
Mequinez, Morocco ; N. montrouzieri, guttata, and expansa, Gassies, J. de 
