— 351 — 



the palatal armature only the fifth fold near the lower 

 suture is forraed. This is the first instance which has corne 

 under my observation wliere a séries of barriers is in 

 course of formation and it is interesting to find that the 

 pariétal barriers are the first to be formed : and also the 

 first to be absorbed. 



PlECTOPYLIS INFRALEVIS n. sp. 

 (PI. VII, fig. 4, 5,6). 



Testa dextrorsa, latc umbilicata, discoidea, fulvo-cornea . 

 Spira depressa, apice prominulo. Anf7\ 7 paululum convexi, 

 regulariter crescentes, sutura parum profunda juncti, striis 

 incrementi et lineis spiralibus exilissimis superne decussati, 

 ultimus inferne nitens, supra peripheriarn subangulatus, in- 

 ferne rotundatus, circa umbilicum obscure angulatus, prope 

 aperturam vix dilatatus, br éviter descendens et deflexus. Aper- 

 tura subovata, obliqua, marginibus callo flexuoso, denticulum 

 debilem, elongatum et obliquum ferente, junctis. Peristoma 

 paululum incrassatum ac reflexum . 



Laminse pariétales 2 verticales, divergentes, antica bre- 

 vissima. Laminas palatales 6, prima depressa, ceterœ semicir- 

 culares. 



Shell dextral, widely umbilicated, discoid, fulvous 

 brown, duU above, shining below, fmely striated and 

 decussated by close fine spiral Unes as far as the periphery. 

 Spiredepressed,apexprominent, suture shallow. Whorls7, 

 slightly convex, increasing regularly, the last subangu- 

 lated above the periphery, rather tumid belovs^, obscurely 

 angulated round the w^ide funnel shaped umbilicus, a 

 trifle dilaled behind the peristome, shortly descendiûg 

 and rather deeply deflexed in front. Aperture subovate, 

 oblique, margius convergent, united by a slight flexuous 

 callus on the pariétal wall, which bears an elongated 

 oblique denlicle, about 1 mm. from the edge of the callus, 



