-168 MR. HARPER PEASE ON POLYNESIAN LAND-SHELLS. [May 2, 



sian, excepting the type T. porrecta, Gld. I am of opinion, how- 

 ever, that several species described as Truncatelln will prove to 

 belong to the above genns when the operculum is examined. 



Taheitia scalariformis, Rve. 



Truncatella scalariformis, Rve. Proc. Zool. Soc. 1842, p. 197- 

 Truncatella arcticostata, Mouss. Journ. de Conch. 1869, p. 68. 

 The above was first collected by the late Mr. Cuming at the 

 island of Annaa, and since by Mr. Garrett. It is common about the 

 roots of the cocoa-nut trees, and is the only species of its genus in- 

 habiting the above locality. 



Truncatella concinna, Pse. 



T. imperforata, cylindracea, elongata, tenuiuscula, nitida, alba, stra- 

 minea vel rufo-cornea, confertim et recte costulata, costis in anfr. 

 ultimo circa 31; anfr. superst. 4, plano-convexi, ultimus ad basin 

 cristo-costatus ; apertura subobliqua, ovalis, postice vix angulata ; 

 perist. simplex, continuum, subincrassatum, album, adnatum. 



Long. 7, diam. 2| mill. 



Hab. Insula Apaiang (Kingsmill) . 



The species nearest allied to the above with which I am acquainted 

 is T. scalariformis, Rve. 



Truncatella costellifera, Pse. 



T. crassa, non rimata, elongata, turrito-cylindracea, parum nite?is, 

 rubello-flavescens, longitudinaliter costata, costis rectis, com- 

 pressis, in anfr. ultimo circa 20; anfr. persistentes 5, convexi, 

 ultimus circa basin compresso-costatus ; apertura vix obliqua, 

 ovalis ; perist. simplex, continuum, adnatum ; labrum dextrum 

 acutum, intusvix incrassatum, extus prope marginem fortiter cos- 

 tatum, costa compressa, prominens, circa basin extensa, cum costa 

 umbilicali continua. 

 Long. 7, diam. 2\ mill. 

 Hab. Insula Vavau {Brazier). 



The chief peculiarity of the above species is the stout rib encircling 

 the outer lip, which continues around the base, connecting with the 

 usual umbilical rib, of even size throughout ; there is no trace of an 

 umbilical fissure. It was collected at the above locality by Mr. 

 John Brazier. 



Genus Plecotrema, H. & A. Ad. 



Two species of the above genus inhabit the Hawaiian Islands, viz. 

 P. striata, Phil., and P. clausa, H. & A. Ad. 



Dr. Philippi had probably both species before him when his 

 description was drawn up ; that by Dr. Pfeiffer of the same species 

 (Mon. Auric. 1856, p. 104) is more accurate. The description of 

 P. clausa by Messrs. Adams agrees more strictly with the form I 

 adopt as the type of that species than the one subsequently pub- 

 lished by Dr. Pfeiffer in ' Novit. Conch.' vol. i. p. 15. 



