500 Mr. W. H. Benson on some forms of Stenothyra. 



compression. It varies much in size. It was communicated to 

 me by Dr. Cantor in 1842, and has been diffused under the MS. 

 name above quoted, both in England and on the Continent. 

 That name however was transferred, by some accident, to the 

 following shell, under the impression that it had been so named 

 by Sowerby. This circumstance may lead to some confusion, 

 but the very different characters of the two species will permit 

 of rectification on a cursory comparison. 



Stenothyra jjolita, Sowerby. 



Testa arcuato-rimata, ovato-pyramidata, leevi, exilissime confertim 

 oblique striata, striis autice fortioribus, punctis (interdum elon- 

 gatulis) lineas remotas spirales iuterruptas efformantibus, fusco- 

 castanea vel castanea, spira elongato-conica, sutura impressa, 

 apice acuminate ; anfractibus o\, supremis valde convexis, ultimo 

 antice celeriter descendente, f testae sequante, ventre majori pla- 

 nato, latere siuistro compresso, angulato, basi transverse cristato- 

 carinata, circa periomphalum compresso-ciugulatum sulcis nonnullis, 

 peritrema trausgredieutibus, insculpta ; apertura A-ix obliqiia, ovata, 

 superne leviter angulata, peristomate undique pianato, callo parie- 

 tal! mediocri pallido. Operculo concave, albide, duriori, epidermide 

 fusco-castaneo iuduto. 



Long. &\, diam. major A\, min. 3 mill. — Sp. mus. nest. 



Hab. inpaludibus lusulse Singapore. Detexit amicus Dr. J. F.Bacon. 



Syn. Nematura poUta, Sow. teste A. Adams, Pr. Z. S. 1851. 



Dr. Bacon sent me a single specimen from Singapore, from 

 the marshes of which island he procured many species of Aui'i- 

 culad(S, including some new shells lately described by PfeifFer. 

 The specimen is more characteristic, and darker in colour than 

 the typical one transmitted by Mr. Cuming from his collection 

 for comparison. The species is easily known by its pinched 

 carinate base, form, and peculiar sculptui-e. On the back of 

 the shell the puncta are closer, and more disposed to form im- 

 pressed continuous lines than on the flattened front. 



Stenothyra minima, Sow., 



CharleswortVs Mag., April 1837, vol. i. p. 217, fig. 22 b, 

 where this shell was very cursorily described as Nematura 

 minima, Sowerby, in the following terms : — 



" This is about one-fifteenth of an inch in length, and is trans- 

 lucent; it has a smooth polished surface and a small umbilicus, 

 and it is of a light brown colour." 



It was subsequently described by Mr. Arthur Adams in the 

 P. Z. S. July 1851, as follows, and was erroneously recorded as 

 N. minima, Benson : — 



