10 FLAMMULINA. 



( Tasmanian Species.') 



L. csesa Cox. iii, 261. L. henryana Pett. 



coesus Cox. L. pictilis Tate. 



v. occulta Cox. iii, 264. 



Genus FLAMMULINA Martens, 1873. 



Flammulina MTS., Grit. List Moll. N. Z., p. 12. 



Gerontia HUTTON, Trans. N. Z. Inst. xv, p. 135. PILSBRY, 

 Nautilus vi, p. 55 ; Manual viii, p. 64. Family Pkenacohelicid<r 

 SUTKR, Trans. N. Z. Inst. xxiv, p. 270, 1892. 



Shell thin, varying from discoidal to subtrochiform, umbilicated or 

 perforated, the perforation sometimes closed ; generally somewhat 

 translucent ; surface striate or ribbed, often decorated with reddish 

 flammules. Embryonal 1-U whorls smoother, often spirally 

 striated. Aperture rounded lunar, lacking folds, teeth or internal 

 callus ; the lip thin and simple, somewhat dilated at the columella. 



Animal with a narrow foot bearing a mucous gland at the tail, 

 sometimes surmounted by a papilla. Genitalia unknown ; mantle 

 subcentral, its margin even, and slightly reflexed over the peristome 

 of the shell. 



Jaw delicate, composed of thin vertical laminse firmly soldered 

 together but showing more or less of the overlapping edge of each 

 plate. 



The radula exhibits a considerable amount of variation in the 

 different species, but the extremes are connected by all intermediate 

 forms. That of F. ( Thalassohelix) ziczac, drawn by the author from 

 an Auckland specimen, on pi. 3, fig. 28, may be taken as an example- 



The central tooth has a moderate or long mesocone, ectocones being 

 entirely lacking in some forms, present and well developed in others. 

 The laterals are not crowded, and generally have a long mesocone 

 and short ectocone, but often the entocones also are developed, mak- 

 ing the tooth tricuspid. The marginals are formed by the shorten- 

 ing of the basal-plate and increase in size and obliquity of the cusps, 

 the mesocone in most forms remaining distinctly larger, sometimes 

 becoming bifid, probably by fusion with the entocone. The ectocoue 

 persists on the marginal teeth, either as a simple cusp, as in F. ziczac, 

 or becoming split into several distinct points, as in the Allodiscus 

 species, and in the latter the tooth becomes very wide. In one sub- 

 genus, Phactissa, the ectocone is lost on the marginals, but they retain 

 the characteristic rhomboidal basal-plate ; and Thalassohe/ix exhib- 

 its a form of marginals connecting Phacussa with the more normal 



