. LANISTES. 169 



extremities ; columella oblique, reflected over part of the umbilicus ; 

 umbilicus forming a lengthened areabehind the columella. Northern 

 shores. Fig 364, L. Pallidula. 

 LAGENULA. Montf. A genus of microscopic Foraminifera. 

 LAMELLATED. {Lamella, a thin plate.) When the layers of 

 which a shell is composed, instead of being compacted iuto a 

 solid mass, are separated, overlying each other in the manner of 

 tiles, with the edges prominent, the structure is said to be lamel- 

 lated or foliaceous. 

 LAMELLIBRANCHIATA. Bl. The third order of the class 

 Acephalophora, Bl. consisting of bivalve shells, divided into the 

 families Ostracea, Subostracea, Margaritacea, Mytilacea, Polydon- 

 tes, Submytilacea, Chamacea, Couchacea, Pylorides, Adesmacea. 

 LAMELLIPEDES. 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. 

 LAMPAS. Montf. Lenticulina, Bl. A genus of microscopic 



Foraminifera. 



LAMPRODOMA. Sw. A genus of " Olivinee," Sw. thus described : 



— " Mitriform ; spire produced, conic ; resembling Mitrella in 



shape, but the suture is channelled ; the aperture effuse at 



the base, contracted above ; lower half of the pillar with 6 to 7 



plaits. Volutella, Zool. 111. ii. series, pi. 40. f. 1. (fig. 86.)" 



Sw.p. 321. 



LAMPROSCAPHA. Sw. A sub-genus of " AnodontinEe," Sw. 



thus described : — " Shell not winged, elongate, pod-shaped ; teeth 



none ; bosses near the anterior extremity. Tropical America 



only? L. ? elongata. Siv. Zool. 111. i. 176. ensiforme, Spix. 



Braz. Test, siliquosa. Braz. Test, pygmeea. lb." Sw.p. 381. 



LAMPROSTOMA. Sw. A sub-genus of Canthorbis (Trochus), 



described at p. 350, Lardn. Cyclop. Malac. 

 LAMPUS. Humph. Terebratula, Lam. 

 LANCEOLATE . Lengthened like a lance. 

 LANISTES. Montf. Reversed species of Ampullaria, fig. 319. 



