LITTORINA. 575 
eyes outside their base. Foot short, broad before, attenuated behind. Radula very 
long. Oviparous, feeding on vegetable matter. 
Living on rocks which are only moistened by the spray of the breaking waves, near 
or even above high-water mark, and very tenacious of life *. 
The Mexican and Central-American species may be grouped into subgenera as 
follows :— 
I. Cencuniris +, n.—Shell tuberculated, rather flattened below and minutely perforated ; aperture 
very oblique, not distinctly angular above; columellar margin not much thickened. 
Operculum typical, oval, paucispiral, with a distinct angle above and rather eccentric 
nucleus. 
Type, ZL. muricata (L.), common in the West Indies. 
In the general form of the shell and the very oblique aperture this species approaches the 
subgenus Tectarius, Val. t, type L. pagodus (L.), and still more nearly to Echinella, Gray, 
type L. cumingi, which latter is distinctly umbilicated. But the operculum of L. muricata 
is not circular, with median nucleus, as in Tecturius and Echinella, but has the form of 
that of L. littorea, as may be seen in several specimens collected by Herr Gollmer in the 
Berlin Museum. Nodilttorina, v. Martens (1897), which is also tuberculated, with normal 
operculum, is distinct from L. muricata by the nearly perpendicular aperture, with very 
broad columellar margin and convex basis of the shell. 
If. Lirrrorinopsis, Morch [Malak. Blatt. xxi. p. 137 (1876) ]; Litorina, section II., P. Carpenter 
[Cat. Mazatlan Shells, p. 351 (1857)].—Shell of moderate size; nearly smooth, with 
impressed spiral lines only, of brownish colour, more or less variegated. Aperture 
distinctly angulated above, moderately oblique, inside pale-coloured, the edge usually 
with. dark dots. 
The typical species, L angulifera, Lam., and the Indian L. scabra (.), have a compara- 
tively thin shell and live on the stems, branches, and leaves of mangrove-shrubs. But 
* Dr. Lister [Hist. Conch. i. 30. n. 28 (1685)] states that he has kept alive a West-Indian species, probably 
L. nodulosa, Pfr., during a whole summer in his garden, apparently far from the sea. The Papuans, in the 
eastern part of the Malayan Archipelago, used to keep alive another species, L. (Tectarius) pagodus, L., for a 
whole year in their chests and presumed that something was not right if the animal died earlier (Rumph, 
Amboinsche Rariteitkamer, 1705, p. 74). 
+ Cenchritis, fem., in Greek, a dry granulated fig, as if beset with grains of millet. Older conchologists 
named this shell “ Reisbrei,” rice-pap, on account of the minute pale tubercles. 
+ Tectus, Montfort [Conch. Syst. ii. p. 186 (1810)], is interpreted by Hermannsen [Indicis Generum Malac. 
primordia, li. p. 532 (1847-49)] and Philippi [Handbuch, 1853, p. 175] to be founded on the type of 
Littorina pagodus (L.), and I have followed these reliable authors in working out the submarine shells of the 
Malayan Archipelago [in Prof. Weber’s ‘Zoologische Ergebnisse einer meee in N iggerlaudiseh Ostindien,’ iv. 
p- 201 (1897) ] and those of the East Coast of Africa [in MObius’s ‘ Ostafrikanische Thierwelt,’ ii. p. 267 (1897) |. 
But on referring to Montfort’s description and figure, it is clear that his type was Trochus mauritianus, Lam., 
Cuarastoriced by the two spiral ridges within the aperture, although he quotes 7. pagodus, L. P. Fischer 
| Manuel de Conchyliologie, p. 817] cites 7’. dentatus, Forsk., as the type of Tectus, Montf.; but that species 
wants the two ridges which Montfort notices in his description and figure. 
