NERITINA. 67 



N. RETROPICTA, Martens. PI. 24, figs. 40, 41. 



Closely striulate, subopaque, olivaceous, with subtriangular yel- 

 low markings, bordered on the basal margin with black, aperture 

 bluish or yellowish, columellar margin sinuated and obtusely dentate 

 in the middle, area light greyish yellow, slightly rugulose. 



Diam. 14-17 mill. 



Southern Japan, Siam, Viti Is. 



I suspect that this will prove a variety of the preceding species. 

 The synonyms are N. obtusa, Reeve, (fig. 41), N. nubila, Martens, 

 and N. obscura, Dunker. 



N. CASTANEA, Hombr. and Jacq. PI. 24, fig. 42. 



Minutely flexuously striulate, somewhat sharply so above, dark 

 brown, with black zigzag longitudinal lines, so obscure that they 

 are not usually visible except when the surface is wetted, epidermis 

 of last whorl appressed to and partially or entirely covering the 

 spire; aperture bluish white, columellar margin slightly sinuous, and 

 scarcely dentate in the middle, area flattened, minutely punctate 

 and rugose. Diam. 15-18 mill. 



Samoa and Caroline Islands. 

 N. propinqua, Mousson is a synonym. 



N. RETUSA, Morelet. PI. 24, figs. 43, 44. 



Subrugosely striate, soiled olivaceous, with scarcely visible brown- 

 ish maculations, with short spines on the shoulder in the young state 

 which are mostly lost in the adult; aperture yellowish white, the 

 columellar area becoming orange color behind, edge sub-emarginate 

 in the middle and minutely dentate. Diam. 12 mill. 



New Hebrides. 



N. SOWERBYANA, Recluz. PL 24, fig. 45; PI. 25, figs. 46-51. 



Solid, subopaque, closely, faintly striate, shining, yellowish brown, 

 orange brown or rosy, frequently with minute white and red spots, 

 sometimes more or less interruptedly banded or longitudinally 

 strigate with black ; aperture usually bluish white, columellar mar- 

 gin dentate for most of its length. Diam. 10-15 mill. 



Gulf of Siam, China, Japan, Philippines. 



Great as is the typical difference between this species and N. 

 brevispina, Lam., I have specimens before me which seem to estab- 

 lish a passage between that species and the granular, spineless form 

 of the latter, N. pulchella, (figs 50, 51), Recluz, and N. Sowerbii, 

 Reeve, (figs. 48, 49), are synonyms. 



