LEPTOCONCHUS. 55 
Acephalophora, Bl. containing the families Ostracea, Subostra- 
cea, Margaritacea, Mytilacea, Polydontes, Submytilacea, Cama- 
cea, Conchacea, Pylorides, Adesmacea. 
LAM ELLIPEDES. Lam. (Lamella, a thin plate; pes, a foot.) 
The third section of the order Conchifera Dimyaria, containing 
bivalves, with the foot of the animal broad and thin; divided 
into the families Conchacea, Cardiacea, Arcacea, Trigonacea, 
Nayades. Fig. 111 to 152. 
LAM’PAS. Montf. Lewnricutina, Bl. A genus of microscopic 
Foraminifera. 
LANIS'TES. Montf. Reversed species of Ampunuaria, fig. 319. 
LAPLY’SIA. v. Aplysia. 
LAPLYSIA’CEA,. Lam. A family belonging to the first section 
of the order Gasteropoda, Lam. containing the genera Aplysia, 
and Dolabella. Fig. 254, 255. It should be Aplysiacea. 
LATERAL (Latus, side.) Teeth. Are those which taking their 
rise near the umbones proceed to some distance towards the sides 
of the shell; as distinguished from the cardinal teeth, which re- 
ceive their full developement close to the umbones. 
LAT’ ERAL muscular impressions. Are those which are piaced at 
a distance from each other, on the opposite sides of the shell. 
LATYRUS. Montf. A genus composed of species of Fusus, Auct. 
which have an umbilicus, and are turriculated. 
LEGUMINA‘RIA. Schum. A genus composed of species of 
Solen, Auct. which have an internal, longitudinal bar or rib. 
Fig. 61,8. Radiatus, Lam. 
LENGTH. See Measurement. 
LENTICULAR. (Lens.) Ofa circular, convex form, as Pec- 
tunculus, fig. 134. 
LENTICULINA. Lam. A genus of microscopic Foraminifera. 
Descr. Lenticular, sub-discoidal, compressed, convolute, sym- 
metrical; aperture notched; chambers few in number; visible 
on the exterior, radiating from the centre of the disc. 
LE’PADICEA. Bl. First family of the class Nemantopoda, BI. 
containing the genera Gymnolepas, Pentalepas, Polylepas, and 
Litholepas. 
~LE'PAS. (Aesas, lepas, a rock.) The Linnean name Lepas con- 
tains all the Cirripedes, or Multivalves. (Fig. 14 to 43.) It was 
formerly applied to the Limpets or Patella. In fact, the ancient 
definition was, ‘‘ Concha petre adherens,’ and would apply to 
any shells attached to rocks. 
LEPTAYNA. Dalman. A genus belonging to the Brachiopoda 
thus described: “Hinge compressed, rectilinear, frequently 
exceeding the width of the shell,” Forming part of the genus 
Propuctus, Sow. Fig. 206, L. depressa. 
LEPTOCON’CHUS. (Aeros, leptus, thin; Koyxos, conchos, shell. ) 
This shell resembles a- young Magitus in general appearance, 
