OPEAS CLAVULINUM. 135 



lucent margin 'below. Aperture subvertical; outer lip thin, 

 arched forward in the middle, somewhat retracted below. 

 Columella subvertical, with a distinct spiral twist below; its 

 edge reflexed above. Length 12, diam. 3.3, longest axis of 

 aperture 3.3 mm. 



Ryukyu Is.: Okinawa (Hirase). 



Opeas obesispira PILS., Proc. A. N. S., Phila., 1904, p. 638. 



Very closely related to 0. mauritianum, but the whorls 

 are more convex and smoother, and the sutural margin 

 distinct. 



3. 0. CLAVULINUM (Potiez et Michaud) . PI. 23, figs. 17, 21, 22. 



" Shell turrited, fragile, glassy, shining, diaphanous; 

 whorls 6, convex, the last larger; aperture ovate above and 

 to the left angular; peristome simple, acute; apex obtuse. 

 Length 8 mm. 



"This shell makes, so to speak, a transition from Bui. 

 clavulus to Bui. oryza, which is the shortest; its last whorl is 

 proportionately larger than that of its two congeners, its 

 summit is more obtuse and it is a little more ventricose." 

 (P. & M.} 



Bourbon Is. (P. & M.) ; Mauritius (Nevill) ; Seychelles 

 (Brauer). 



Bulimus clavulinus P. & M., Galerie des Mollusques du 

 Mus. de Donai i, p. 136, pi. 14, f. 9, 10, 1838. Opeas 

 clavulinum MARTS., Land und Siisswasser-Mollusken der 

 Seychellen, in Mittheil. Zool. Sammlung Mus. f. Naturkunde 

 Berlin, i, p. 23, 1898. 



The original description and figures (fig. 17) are given. 

 The species has been so variously identified, that references 

 to the literature would be useless and misleading. 



The species I take to be clavulinum is related to johanni- 

 num and to mauritianum, but it is smaller than the latter, 

 with the spire less swollen above. The specimens figured 

 are from Mauritius (pi. 23, figs. 21, 22). The shell is 

 openly perforate, pale yellowish-corneous; striate, but the 

 sculpture is decidedly weaker than in 0. gracile ; glossy. 

 The sides slope almost straightly, but are a little convex 



