146 



HELICID^. 



two lower arms of the main fold (see fiir. 77 c, which shows part 

 of the parietal wall with its folds). Of the palatal armature, the 

 lirst, secoud, and third folds are more elevated ; the first is bilobed, 

 and above the posterior portion of the second occurs a very short 

 additional fold. The vertical lamina is also more elevated, and in 



b c 



Fig. 77. — Tlectopylis hcJi>>oni, var. hreviplica. 



place of the usual denticle posteriorly to its lower extremity is 

 found an elevated ridge quite united to the plate. Fig. 77 a shows 

 the anterior and fig. 77 h the posterior aspect of both armatures. 

 The specimen figured is in the collection of Mr. Ponsonby. 



117. Plectopylis repercussa, Gould. 



Helix repercussa, Gould, Proc. Boston Soc. Nat. Hist, vi, 1856, p. 11; 



Hanley & Theobald, Conch. Ind. 1870, pi. 13, tig. 4. 

 Helix {Ph'ctopylis) repercussa, Stoliczlia, J . A. S. B. xl, 1871, p. 218 ; 



Nevill, Hand List, i, 1878, p. 72. 

 Plectopylis repercussa, Gude, Science Gossip, n. s. v, 1898, p. 74, 



fig. 78. 

 Plectopylis (s. s.) repercussa, Gude, op. cit. vi, 1899, p. 148. 



Oriqinal description: — "T. siuistrorsa, discoidea, supra planulata, 

 infra concava, plicato-striata etlineis volventibus superne inscalpta, 

 castanea ; anfr. utroque + , ultimo vix augulato, prope apertiiram 

 defiecto ; apertura despiciens, oblique lunata, peritremate retlexo, 

 postice callo augulato juucto ; lamellis palatinis duabus intro 

 volventibus, quarum una ad angulum inconspicua. 



Diam. 1 [=25-5 mm.], alt. ^ poll. [=7-7o mm.]." 



Hah. Burma : Tavoy and Mergui {Benjamin) ; Moulmain 

 {Theolald, StoUczl-a). 



The diagnosis by Gould is somewhat vague, and as the species 

 was not illustrated, subsequent authors considered it to be 

 synonymous with P. bensoni, from which species, however, it 

 differs in outward appearance as well as iu its armature. The 

 shell is sinistrorse, disk-shaped, pale corneous, finely striated, the 

 upper side being strongly decussated by spiral lines, almost 



