182 OPEAS, POLYNESIA. 



subrhomboidal, the peristome unexpanded, acute, the right 

 margin arched forward, columellar margin reflexed, ap- 

 pressed. Length 12.75, diam. 4.75 mm. (Mlldff.) 



Caroline Is.: Ponape (Kubary). 



Opeas pruinosum MLLDFF., Journ. of Malacol. vii, 1900, 

 p. 114. 



"This species belongs to the group of 0. clavulinum 

 P. & M. but is well characterized by the curious sculpture 

 which gives it a somewhat hoary aspect. 7 ' 



90. 0. KUSAIENSE Pilsbry, n. sp. PI. 16, figs. 89, 90, 91. 



Shell perforate or rimate, turrited-conic, rather short, with 

 nearly straight lateral outlines, olivaceous-corneous, a little 

 translucent, often more or less varied with white spots and 

 dots; not glossy, but having a silky luster. Sculpture of 

 very close, fine, deeply cut, strongly arcuate strict. Whorls 

 7 to 7^, quite convex, parted by a well-impressed suture, the 

 last whorl rounded below. Aperture ovate-rhombic. Coin- 

 mella concave in the middle, somewhat protruding below, 

 where it tapers or is obliquely subtruncate. Columellar mar- 

 gin reflexed -as usual. Length 9.5, diam. 3.6, length aperture 

 3.4 mm. 



Length 10.3, diam. 3.8, length aperture 4 mm. 



Caroline Is.: Kusaie (L. M. McCormick). 



A stouter, more compact shell than 0. javanicum, but with 

 similar sculpture. 0. pruinosum Mlldff. is doubtless closely 

 related, but is larger with differently developed sculpture. 

 In 0. kusaiense there seem to be delicate cuticular lamellae 

 on the rib-striae, which gather and hold a coating of soil. On 

 washing the shell, these laminae are removed. The most obese 

 specimen in the type lot of over fifty shells measures, length 

 9, diam. 3.9, aperture 3.9 mm., whorls 7. 



XI. Polynesian and Micronesian Species. 



Opeas gracile and 0. oparanum are the prevalent species 

 in this region. In the Hawaiian islands a number of wide- 

 ranging forms have colonized, the following being known : 

 0. oparanum (pyrgiscus), 0. mauritianum, 0. clavulinum 



