74 SUBULINA. 



near the sea-shore). Subulina mamillata Craven, CROSSED 

 Journ. de Conch. 1881, p. 201 (Nossi-Comba, E. Marie). 

 CROSSE & FISCHER, Moll. Madag. pi. 24, f . 4. 



The above references apply only to the occurence of 

 S. octona in the Eastern Hemisphere. 



It is generally and I believe correctly held 'that this species 

 in the tropics of the Old World is an emigrant from America. 

 Dr. Boettger has already remarked that it seems to have only 

 lately invaded the Indo-Malayan and Papuan islands, for 

 earlier and closely observant naturalists made no note of it. 

 It appears first to get foothold in centers of trade and agri- 

 culture, and to spread with extraordinary rapidity into neigh- 

 boring districts. 



Subulina in a state of nature appears to be restricted to 

 Africa and America; but by commerce S. octona has spread 

 to the East Indies and as far as the New Hebrides. I have 

 examined specimens from West Africa, the Seychelles, Cey- 

 lon, Sumatra and Ternate, and am satisfied of their identity 

 with 'the Antillean 8. octona. The figures on plate 12 are 

 from Ternate shells. It was first noticed in New Caledonia 

 in 1887 or 1888, appearing by thousands (Layard, P. Z. S. 

 '88, 358). 



Reproduction begins before the shell has attained two-thirds 

 its maximum size, and usually several eggs may be seen 

 through the shell within the penultimate whorl. The egg- 

 capsules are hard-shelled, white and flattened, measuring 1.8 

 xl.5 mm. (pi. 12, figs. 11, 12). 



West African species. 

 2. S. MORELETI Girard. PL 11, fig. 86. 



Shell conic-turrited, thin, but slightly shining, covered with 

 a dark reddish-brown epidermis, and ornamented from the 

 summit with a quite prominent, narrow-spaced, nearly regu- 

 lar, straight and quite oblique costulation. Spire of 9 con- 

 vex whorls, separated by a deep suture, the convexity de- 

 creasing from the first to the last. Summit quite acute. Last 

 whorl obtusely carinate, occupying nearly a fourth of the 



