COLUMELLA. 95 
free valve, entering a corresponding indenture in the other; and 
an oblong, shelly appendage fixed by an internal cartilage in a 
groove under the umbones. Muscular impressions, two in each 
valve, one elongated, the other uniform. Obs. This shell is 
like Chama in general form, but distinguished by the clavicle or 
shelly appendage from which its name is derived. Fig. 75. 
CLEO'DORA. Per. et Les. Fam. Pteropeda, Lam. Thecosomata 
Bl. Desc. Thin, transparent, pyramidal; with flat, alate sides 
and oval aperture. Fig. 221. C. Cuspidata. 
CLISIPHONITES. Montf. Microscopic. Lenricunina, BI. 
CLI'THON. Montf. Nerrria spinosa, &c. Auct. fig. 325. 
CLITIA. Leach. Fam. Balanidea, Bl. Order. Sessile Cirri- 
pedes, Lam. Deser. Sub-conical, compressed, consisting of four 
unequal valves, two larger and two smaller, joined together side 
by side, by the interlocking of their dentated edges. Operculum 
consisting of two unequal, pointed-valves. Obs. Clitia is known 
from Creusia, by the articulations of the valves, and by the 
operculum, which in Creusia consists offour valves. Fig. 20. C. 
Verruca, (Lepas Verruca, Gmelin.) 
CLO’THO. Faujas. am. Conchacea. Bl. Deser. “Oval, sub- 
regular, longitudinally striated, equivalve, subequilateral ; 
hinge consisting of a bifid tooth, curved as a crochet, larger in 
one valve than in the other.’’ This description is translated 
from Blainville, who states that he has never seen the shell. 
COBRE’SIA. Hiibner. Vrrrina, Auct. 
COCH'LEATE. (Cochleare, a spoon.) Applied to any shell or 
part which is hollow and oval, as Patelle, &c. The cavity 
containing the cartilage in Mya, fig. 71,is Cochleate. 
COLIMA’CEA. (Colimacées, Lam.) A family belonging to the 
first section of the order Tracneuipopa, Lam. containing the 
genera Helix, Carocolla, Anostoma, Helicina, Pupa, Clausilia, 
Bulinus, Achatina, Succinea, Auricula, and Cyclostoma. The 
numerous genera into which later authors have divided these, 
will be named in the explanation of fig. 264 to 307, as far as they 
have been considered of sufficient importance to be represented. 
COLUMBEL'LA. (Columba, a dove.) Fam. Columellata 
Lam. Deser. Thick, oval or angular; with short spire and 
long, narrow aperture, contracted in the centre, and terminating 
in an anterior canal. Outer-lip thickened and dentated ; inner- 
lip irregularly crenated. Epidermis thin, brown. Operculum 
very small, horny. Obs. Those species of Mitra, which resemble 
Columbella in shape, may be easily distinguished by the plaits 
on the Columella. The Columbelle are marine, and few fossil 
speciesare known. Fig. 430, C. Mercatoria. 
COLUMEL'LA. A solid column formed by the inner sides of the 
volutions of a spiral univalve. It is sometimes described as the 
inner-lip of the aperture, of which it forms a part; but the term 
E 
