PLACOSTYLUS, NEW CALEDONIA. 59 



1887, p. 305 P. monackensis Cr., KOBELT, t. c., p. 104, pi. 25, f. 

 3-5 (1891). CROSSE, J. de C., 1894, p. 275, pi. 9, f. .Bulimus 

 porphyrostomus var. (5, Candida, CROSSE, J. de C., 1874, p. 108, 183; 

 1875, p. 218, pi. 8, f. 2 Placostylus dautzenbergi MARIE MS,, ac- 

 cording to Kobelt. 



This form is considered by Crosse as combining the characters of 

 P. porphyrostomus and P. duplex. It differs from porphyrostomus in 

 its less dull shell, covered with rugosities and malleation more nu- 

 merous and more pronounced ; by its darker and more persistent 

 epidermis ; by the development of a very prominent columellar fold, 

 sub-bifid interiorly and abruptly truncated at the base, instead of 

 gradually tapering as in the other species ; and finally, it differs by 

 the broader aperture, which is less obliquely placed, and differently 

 colored ; the color of the interior of the aperture of P. monackensis 

 being light, and varying between pure white, citron yellow and light 

 orange yellow, while that of P. porphyrostomus is [generally] deep 

 purple brown. 



;< P. monackensis differs from P. duplex in being more lengthened, 

 more strongly malleated, the last whorl of the spire proportionally 

 less inflated ; by the development of the columellar fold, which is 

 very prominent, sub-bifid interiorly and abruptly truncated below 

 instead of being tapering as in P. duplex, and finally by the light 

 color of the aperture, which in P. duplex is deep purple-brown as in 

 P. porphyrostomus." 



Fig. 26 is Crosse's type. Fig. 27 a rare white-mouthed form, 

 originally described as a variety of P. porphyrostomus. 



P. DUPLEX (Gassies). PI. 29, fig. 41. 



Shell imperforate, solid, longitudinally rugose-striate, strongly 

 malleated ; grayish-wliite under a yellowish-chestnut epidermis, or- 

 namented with rippled chestnut lines which disappear above. 

 Whorls 7. Aperture oblong-ovate, auriform, columella thick, spread- 

 ing, with an oblong fold ; the white parietal callus bearing a conical 

 tubercle ; outer lip deeply sinused above, very thick and reflexed 

 below. Interior violet-purple, peristome white. Length 63, diam. 

 32 mill. 



Island of Nou, New Caledonia (Marie). 



Bulimus duplex GASS. Faune, ii, p. 64. Placostylus duplex 

 CROSSE, Journ. de Conchyl. 1894, p. 273, pi. 9, f. 3 (figure of type 



