PLACOSTYLUS, NEW CALEDONIA. 35 



Group of P. fibratm. 



This is the most prolific New Caledonian group in species and vari- 

 eties. The latter are apparently endless ; and as no distinction has 

 yet been made between individual variations and racial divergence, 

 the subject is in almost inextricable confusion. Milton's line " All 

 hope abandon ye who enter here " serves as well for those entering 

 upon the study of these Placostyles as in its original application. 

 Only very extensive local series collected by an observant and careful 

 naturalist can illuminate this subject. 



P. ALEXANDER (Crosse). PI. 13, figs. 1, 2 ; pi. 14, figs, 6, 7, 8. 



Shell imperforate, ovate-conic, thick, strongly compressed from 

 front to back, the two sides subangular ; white under a reddish- 

 chestnut cuticle ; smoothish or irregularly wrinkled-striate. Whorls 

 6, the last large, much wider, flattened. Aperture large, whitish- 

 yellow within, the peristome pale orange-yellow ; outer lip reflexed, 

 strongly thickened, slightly sinuated within, above ; columella thick- 

 ened, bearing two low callosities. Length 85, diam. 50 mill. 



Length 103, diam. 65, length of aperture 69 mill, (largest seen). 



Length 78, diam. 51, length of aperture 52 mill, (smallest seen). 



New Caledonia : Ina, near Ougap ( Wagap) ; also at Kanala (?) 



Bulimus alexander CROSSE, Revue Zoologique, (2), vii, pp. 34, 

 83, pi. 4, f. 2, 3 (1855) ; Journ. de Conchyl. 1864, p. 108 GASSIES, 



Faune Conch. N. Caled. i, p. 42, pi. 3, f. 1 (1863) PFR. Monogr. 



iv, p. 369; vi, p. 13; viii, p. 18 (varieties). 



Placostylus alexander KOBELT, Conch. Cab. Placostylus, p. 27, 

 pi. 7, f. 1, pi. 8, f. 1 (1891). 



Var. PROCERULA : Bvlimm alexander, var. a. CROSSE, Revue 

 Zool., p. 34, 83, pi. 4, f. 1 (1855). GASSIES, Faune, i, p. 43, 1863. 

 Bulimus alexander, var. b. CROSSE, Journ. de Conchyl., xii, p. 

 109 (1864) GASSIES, Faune ii, p. 74 (1871.)^. a. var.procerula 

 PFR., Monogr. viii, 18. Placostylus alexander var. procerula KOB- 

 ELT Conch. Cab., Placostylus, p. 29. 



Var. OUAGAPENSIS ; Bulimus alexander, var. g, CROSSE, Journ. 

 de Conchyl., xvii, p. 179 (1869) var. ouagapensis PFR., Monogr. 

 viii, 18. Placostylus alexander var. ouagapensis Kobelt, Conch. Cab. 

 Placostylus, p. 29. 



Var. CRASSA : B. alexander var. d CROSSE, Journ. de Conchyl. 

 xviii, p. 243, 414 (1870). GASSIES, Faune Conch. Nouv. Caled., 



