FLAMMULINA. 19 



finely tuberculate. Tentacles moderately long, cylindrical. Habits 

 very active ; emitting, when crawling, abundance of transparent 

 mucous. PI. 9, fig. 27. 



Jaw low, arcuate, the ends rounded, recurved ; with a blunt 

 median projection below ; crossed by numerous fine folds (pi. 9, 

 fig. 28.) 



Dentition : all teeth having basal-plates of the usual quadrate 

 form. Centrals tri cuspid, the mesocone projecting beyond the lower 

 margin of the basal-plate, side cusps not quite reaching half the 

 length of the plate. Inner laterals similar but slightly oblique ; on 

 he outer laterals the entocone increases and theectocone diminishes. 

 Marginals with the basal-plate low and wide, bearing the large, sub- 

 equal ento and mesocones, and a bifid or trifid ectocone ; the extreme 

 marginals having an irregularly serrated edge (pi. 9, fig. 29.) 



The trochoidal shell resembles that of the keeled Thalassohelix 

 species, but the low, wide and multicuspid marginal teeth offer a 

 contrast to those of that group. 



Our knowledge of the anatomy of this group is due to Charles 

 Hedley's researches (Proc. Roy. Soc. Queensl. v, p. 152, and vi, p. 

 250) ; the figures were drawn from specimens collected on Little 

 Nerang Creek, Queensland, where it was found abundantly on the 

 trunks of trees. 



F. delta Pfr. ii,215. 

 conoidea Cox. 

 fenestrata Cox. 



Subgenus MONOMPHALUS Ancey, 1882. 



Monomphalus . . . . Le Naturaliste 1882, p. 86 (M. bavayi and 

 heckelianus') ; ANCEY, Bull. Soc. Mai. Fr. v, p. 370. TRYON, 

 Manual i, p. 114. 



Shell thin, discoidal^the spire slightly concave, umbilicus reduced 

 to-a mere chink ; periphery broadly rounded. Sculptured with fine 

 riblets, the embryonal whorl showing very fine spiral striae. Aper- 

 ture vertical, lunate, lip thin, dilated over the perforation. Type 

 F. rossiteriana Crosse, pi. 3, figs. 7, 8, 9. 



Soft parts unknown. Distribution, New Caledonia. 



This group is very similar in shell characters to Allodiscus, and 

 the two may require to be united. They are here retained separate 

 because the anatomy of the New Caledonian forms is unknown, and 

 may prove sufficiently different. 



