378 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



Ptyciiobon pseutes, n.sp. PI. XVIII, Fig. 12. 



Sliell sub-discoidal, spire sliglitly raised, narrowly umbilicate, 

 sutures deeply impressed, last whorl descending to about half-way 

 down the peiiultiniate whorl. Colour pale reddish brown with 

 darker llammulate markings. Whorls -^i, well rounded ; first whorl 

 and a half, constituting the protoconch, radially sculptured with 

 fine slanting threads, abruptly ceasing when tlie adult sculpture 

 of straight, even-spaced lamelloe commence, about sixty being counted 

 on the first adult whorl ; the lamellae regularly increase in number, 

 but the spaces widen a little witli age, and minute threads occur 

 betwixt. Umbilicus narrow and deep, exposing the previous whorls, 

 about one-fourth the diameter of the shell. Aperture lunate, lip thin. 

 Apertural armour : well inside on the centre of the parietal wall is 

 situated a long bifurcate lamella ; on the columella are two separate, 

 somewhat crass, conical teeth, the basal one the larger; on the inside 

 of the outer lip, situated far back, are six lamellte, one in the npper 

 bend of the whorl almost unnoticeable and five even-spaced ones 

 lower. Diam. max. 1*75, min. l'6mm.; alt. 9mm. 



Ilah. — Sunday Island, Kermadec Group. Living under stones, 

 rotten wood, and dead nikau leaves. 



PxYcnoDON AMANDUs, n.sp. PL XVIII, Fig. 11. 



Shell sub-discoidal, spire slightly elevated, narrowly umbilicate, 

 last whorl descending to about one-third the depth of the penultimate 

 whorl. Colour white. Whorls and sculpture as in preceding. 

 Aperture regularly lunate, outer lip thin, sharp. Apertural armour : 

 much as in preceding; on the top of the outer lip inside is a veiy 

 small thin lamella which is almost unnoticeable; four equal-placed 

 lamellae can be seen situated well back on the iuside of the outer lip. 

 Diam. max. 1 75, min. I'D ram. ; alt. 1 mm. 



Hab. — Sunday Island, Kermadec Group. Living under stones, 

 rotten wood, and dead nikau leaves. 



This is one of the quaint puzzles which occur to the thinking 

 collector. To the systematist handling the shells it would only 

 appeal as a well-marked colour variety, yet I am quite satisfied 

 it is a well-differentiated species. I studied it on the island for 

 nine months, and thougli the only appreciable difference was the 

 colour, it occurred separately from F. pseutes and was always 

 recognizable ; it occurred all over the island, yet no intergradation 

 as regards colour was met with. I have described a typical shell, but 

 as regards the apertural characters some P. pseutes, Pteiifer, seem to 

 show exactly the same. 



I note that of a Tasmanian shell Petterd & Iledley (Rec. Austr. 

 Mus., vol. vii, p. 288, 1909) write: '■'■ Endodoiita antialba, lieddome. 

 Noted for the fact that half the specimens are milkwliite, and the 

 balance brown colour." I do not know whether the conditions under 

 which this shell lives have been reported upon, and therefore cannot 

 be sure whether it provides a parallel case to the pair I have separated. 

 In view of my experience, field observations of antialba, Beddome, 

 might prove interesting. 



