58 LITTORINA. 
LINGULI'NA. D’Orb. A genus of microscopic Foraminifera. 
LIN’THURIS. Bl. A genus of microscopic Foraminifera. 
LIP. v. Lasrum and Lasium. 
LIPPIS'TES. Montf. A genus of microscopic Foraminifera. 
LI'THODOMUS. Cuv. (Acéos, Lithos, stone; Aédpa, doma, house. ) 
Fam. Mytilacea, Lam. Descr. Transverse, elongated, cylindri- 
cal, equivalve, with the extremities rounded, and the posterior 
extremity rostrated; umbones not prominent, terminal; hinge 
straight, destitute of teeth; ligament linear, most conspi- 
cuous within; muscular impressions, two. Obs. The shells com- 
posing this genus differ from Modiola not only in the cylindrical 
form, but also in the circumstance from which the generic name 
is derived, i.e. of their living in stones. Thus while the form 
and structure of the shell bring it near the Mytili, or Muscle 
shells, the habits of the animal cause it to approach the Litho- 
phagi, or rock-eating molluscs of Lamarck. L. Dactylus, is the 
Mytilus Lithophagus of ancient authors. Fig. 161, L. Dactylus. 
LITHOLE’PAS. Bl. (Av6os, dithos, stone; demas, lepas, rock.) De 
Blainville’s name for Lyrnorrya, Sow. 
LITHOPHA’GIDAL. Lam. (Ardos, lithos, stone; ayo, phago, eat 
orgnaw.) A family of the order Conchifera Dimyaria, Lam. 
consisting of terebrating bivalves, gaping anteriorly, having no 
accessary valves ; and containing the genera Saxicava, Petricola, 
Venerupis, to which are added other genera enumerated in ex- 
planation of figures 91 to 97. 
LITHOTRYA. Sw. (Acéos, lithos, stone; rpve, truo, to bore 
through.) Fam. Pedunculated Cirripedes, Lam. Deser. Eight 
unequal valves, forming a laterally compressed cone, the lower 
central valves being very minute; pedicle fleshy, scaly at the 
upper extremity; fixed at the base in a patelliform shelly support. 
Obs. This genus derives its name from the power possessed by 
the animal of making dwelling holes in stones or pieces of rock. 
The remarkable shelly cup at the base of the pedicle is regarded 
as analagous to the shelly base of the Balanus, so that this genus 
would form an intermediate link between the Sessile and Pedun- 
culated Cirripedes of Lamarck. Fig. 39, L. dorsalis. 
LITTORINA. Fer. (Littus,a shore.) Fam. Turbinacea, Lam. 
Descr. Turbinated, thick; spire acuminated, consisting of few 
whorls, about one-third of the axis in length; aperture entire, 
large, rounded anteriorly; outer lip thickened within, acute; 
columella rather flattened. Operculum horny, spiral, with ra- 
pidly increasing volutions. Ods. The shells composing this 
genus are known from Turbo and Phasianella by the horny 
operculum; and from Trochus, which also has a horny operculum, 
by the small number of the whorls. The Littorine, among 
which may be enumerated the common Periwinkle, are, as the 
name implies, found on the sea shores, feeding upon sea weed, 
inall parts of the world. Fig. 363, L. Vulgaris. 
