1'LACOSTYM'S, l''I.II IS. 107 



1'. -.[ ANENSIS (Garrett). PI. 42, figs. 93, 94; pi. 41, fig. 84. 



Shell umbilicate, oblong-ovate, rather thin but strong, pale buft', 

 zigzag-striped longitudinally with olive or olive-brown, the cuticle so 

 thin as to be often eroded along the front edge of each dark stripe, 

 wanting on the spire, which is buff or reddish-tinted. Surface nearly 

 lustrele>~. sculptured witli growth-wrinkles and densely corrugated 

 spirally, on the spin; decussated by impressed spirals cutting fold-like 

 stria-. Apex obtuse, earlier 2^ whorls pitted. Whorls 5, convex, 

 the last variable in degree of elongation. 



Aperture long-ovate, whitish or light orange within ; peristome 

 expanded, thickened within, varying from orange to white ; columella 

 bearing a *trong, compressed, while, or whitish callous fold above ; 

 the outer margin dilated. 



Alt. 49, diam. 20^-; longest axis of aperture 28^ mill. 



Alt. 41, diam. 20 ; longest axis of aperture 24^ mill. 



Gnau (Gnan) island, Viti </ruii/>. (A. J. Garrett.) 



Bulimus guanensis GARR., Amer. Journ. Conch, vii, 1872, p. 235, 

 pi. 18, f. 8 CROSSE, Journ. de Conchyl., 1875, p. 19. PFR., 

 Monogr. viii, p. 36. Piacostylus gnauensis SCIIMELTZ, Catal. Mus. 

 Godetfroy. vi, p. 81. GARRETT, P. Z. S., 1887, p. 184. Placosty- 

 lus guanensis KOBELT, Conchyl. Cab., p. C4, pi. 15, f. (', 7 (not char- 

 acteristic). 



The shell is smaller than P. elobatus and less strongly sculptured 

 spirally ; P. rambiensis is more delicate and differently colored ; 

 and P. yracilis has the lip decidedly broader. 



The variation in size and contour is remarkable, some shells being 

 much elongated, as in the original figure, while others are short and 

 shaped like P. rambiensis, as in Garrett's type, which is only 41 

 mill, long (fig. 93). The extremes are connected by numerous 

 intervening sizes in the series before me. Garrett writes as follows : 



" This graceful species is common and peculiar to Gnau Island, 

 where it lives on trees and shrubs. It may be recognized by its 

 rather thin texture, oblong-ovate or elongate-ovate form, whitish, 

 yellowish, or reddish horn color, ornamented with longitudinal un- 

 dulating olive green stripes, which are frequently shaded off with 

 white. The surface is rugose, with small transverse corrugations. 

 The aperture is tawny yellow or reddish, rarely white, and the lips, 

 which are but slightly expanded, are more intensely colored than is 

 the throat. Length 45 mill." Types in coll. Acad. Nat. Sciences. 



