OPEAS, COMORO AND MASCARENE IS. 151 



columellar margin nearly straight, a little thickened, glossy, 

 white. Length 9.5, diam. 2 mm. (M. & P.). 



Transvaal: Boksberg (Burnup). 



Opeas mcbeani M. & P., Ann. and Mag. N. H. (7), xii, p. 

 604, pi. 31, f. 8 (Dec. 1903). 



"Differs from its near ally Subulina strigilis M. & P. in its 

 more globular apical whorls, finer striation and smaller aper- 

 ture. In that species, too, the last whorl is not so prolonged 

 proportionately, and the upper whorls are less ventricose 

 than in this new form." Compare 0. gracile. 



V. Opeas of the Comoros, Seychelles, Mauritius, etc. 



The Comoro Is. have a rich and peculiar Stenogyrine fauna 

 of African type, indicative of long isolation. The faunal 

 history of these islands has had nothing in common with the 

 Mascarene and other islands of the region. 



The Mascarene islands owe their Stenogyrine chiefly if 

 not wholly to importation, probably since the period of settle- 

 ment. Their position as ports of call between the East and 

 Europe early brought in Oriental Opeas, a number of which 

 were first described from Mauritius, etc. Any Mascarene 

 Opeas may be expected to turn up in the East; and the ori- 

 ginal center of dispersal of such forms as 0. mauritianum, 

 clavulinum, gracile and javanicum may never be known, 

 though it was doubtless somewhere in the East Indies or 

 southeast Asia. 



The American species 0. goodalli, 0. swiftianum and 0. 

 micra occur as immigrants, the former reported from Rod- 

 riguez, the two latter sent by Nevill from Mauritius. 



27. 0. APICULUM Morelet. PL 23, figs. 12, 13. 



"Shell turrited subulate, thin, closely striate, the earlier 

 whorls costulate-striate ; horny reddish, not shining. Spire 

 elongate, the apex rather acute. Whorls 8, planulate, the 

 last equal to one-third of the entire length of the shell. 

 Columella slightly receding, hardly truncate. Aperture of 

 medium size, semioval. Peristome simple, acute, unexpanded. 

 Length 12, diam. 3 mm." (Morelet). 



