Laoma.] GASTROPODA. 733 



Genus 1. LAOMA, Gray, 1849. 



Laoma, Gray, P.Z.S., 1849, 167. Type: Bulimus? (Laoma) leimonias, 

 Gray. Laoma, Pilsbry, Man. Conch. (2), ix, 8 ; Proc. Acad. N.S. Phil., 

 1892, 403; "Nautilus," 1892, 55. 



Animal heliciform, the mantle subcentral, its edge slightly reflected 

 over the peristome ; no locomotive disc nor mucous pore. Jaw arcuate, 

 composed of 20-24 rhombic or oblong plates which are hairy-papillose 

 and fringed at the upper and lower margins. Radula having the 

 central tooth rather narrow, unicuspid or tricuspid, the mesocone 

 much shorter than the basal plate. Lateral teeth wider, rectangular, 

 with 2 cusps, which are either subequal or the inner one larger. Mar- 

 ginal teeth low, wide, with 2 short cusps, becoming obsolete on the 

 outermost teeth. Reproductive organs simple. Shell more or less 

 trochiform, thin, perforate or umbilicate, the periphery keeled, at least 

 in the young ; horn-coloured, mostly striped radially with tawny. 

 Aperture rhombic, provided with entering lamellge, or without them ; 

 Up thin, simple. 



Distribution. New Zealand, Tasmania, southern and eastern Aus- 

 tralia, and British New Guinea. 



Subgen. 1. LAOMA, Gray, s. str. 



Aperture provided with an entering lamella upon the columella 

 only, or with lamellae upon the columella, parietal wall, and outer 

 and basal lips. 



New Zealand only. 



KEY TO SPECIES. 



A. Suture not margined. 



a. Shell smooth, high-conical ; aperture with 3 lamellae 1 on 

 parietal, 1 on outer, and 1 on basal wall and 1-2 small 

 teeth on columella . . . . . . . . leimonias. 



aa. Shell with membranous plaits. 



b. (i plaits per millimetre, with cilise below suture and on 

 keel of base ; aperture with 2 lamellae 1 on outer 

 wall and 1 at the angle of periphery . . . . ciliata. 



l>b. 1 plaits per millimetre, without ciliae ; aperture with 

 4-6 lamellae 2 on parietal wall, 2 on outer wall 

 (usually absent in the young), and 2 on the base pirongiaensis. 

 aaa. Shell with radiate fine riblets, 15 per millimetre ; aper- 

 ture with lamellae 2 on parietal wall, and 4 on base, 

 far back . . . . . . . . . . elegans. 



B. Suture margined above, by a raised cord on the lower whorls. 



a. Shell finely and regularly striated ; aperture with 3 to 7 

 lamellae 1 on columella, 1 or 2 on parietal wall, none 

 or 1-3 on base, 1 on outer wall . . . . . . marina. 



aa. Shell with 15 riblets per millimetre, 1 lamella on columella poecilosticta. 



1. Laoma ciliata, Suter, 1894. Plate 10, fig. 14. 



Laoma ciliata, Suter, T.N.Z.I., xxvi, 1893 (1894), 136, pi. 21, f. 38, 38a ; 

 Suter, J. de Conch., xli, 275. 



Shell minute, pupiform, perforated, horn-colour, with rather dis- 

 tant membranous plaits with a process below the suture, thin and 



