128 LAND- AND FRESHWATER MOLLUSKS &C. 



margin of the aperture. The specimens vary much in colour, 

 one being nearly uniformly yellowish-white. The largest 

 specimen has a diam. maj. of IT'/j» the smallest only of 

 IS'/^ Mill. 



16. Neritina pulligera Lin. 



Martens, Mart.-Chemn. Conch. Cab. Ed. II, Neritina, 



p. 49, PI. 1, figs. 4 et 5. 



Martens, Suss- u. Brackw. Moll. p. 77. 



One fine specimen. 



17. Neritina suhsulcata Sow. 



Martens, Mart.-Chemn. Conch. Cab. Ed. II, Neritina., 

 p. 142, PL 12, figs. 11 et 12. 



A few fine specimens. 



18. Neritina siibpunctata Reel. var. tricolor Mart. 



Martens, Mart.-Chemn. Conch. Cab. Ed. II, Neritina, 

 p. 180, PI. 18, fig. 19. 



The painting of the only specimen agrees very well with 

 the figure of Martens. 



19. Septaria suborbicularis Sow. 



Martens, Mart.-Chemn. Conch. Cat. Ed. II, Navicella, 



p. 31, PI. 6, figs. 5—14. 



Martens, Suss- u. Brackw. Moll. p. 84. 



One dead shell. 



Rhoou near Rotterdam, April 1906. 



Notes from tlie Leyden Mluseum, "S^ol. XXVIII. 



