549 



centre. The operculum is rather more oblong, and much more 

 strongly lobed : it is generally of grey colour. The external 

 surface is also very slightly striated in direction of the lines of 

 growth . 



On stones in a deep river, Island of Luzon, Phikppines. Cuming. 



6. Navicella apiata (pi. cxvii. f. 14, 15. pi. cxviii. bis. 

 f. 39), Le Guillon, Rev. Zool. 1841, p. 376. 



N. testa rotundato-subtrigona, depressa, extiis obscure nigro 

 reticulatfi, epidermide fusca induta ; apice decumbente, marginem 

 superante ■ intus caerulea, nonnunquam maculis nigris magnis 

 lateralibus duabus ; septo subtrigono ; impressionibus musculari- 

 bus rectiusculis. 



Much depressed and spread out at the sides, rather narrowed 

 in front, so as to give a somewhat trigonal form to the shell. The 

 septum is trigonal, and the muscular impressions straight and 

 narrow. 



Island of Bourbon. 



7. Navicella Cumingiana (pi. cxviii. f. 16, 17, 18), Recluz, 

 Zool. Pro. 1842, p. 157. 



N. testa ovali, convexa, sub epidermide concentrice nigro unda- 

 tim fasciata ; apice magno, marginem superante ; labio interno in 

 medio producto ; operculo subovali, ad terminum bilobato ; im- 

 pressionibus muscularibus latis. 



This species, with the form of N . porcellana, and the produced 

 apex of N. macrocepJiala and N. Luzonica, is remarkable for the 

 shape of the septum, which is curved outwards in the centre, 

 somewhat in the form of a uvula ; the operculum is also peculiar, 

 being rather oval, with two ecmal lobes at the end. 



Lebouka, Feejee Islands; 31. Farges. Islands of Mindinao 

 and Caminguing, Philippines ; on stones in a mountain stream ; 

 Cuming. 



8. Navicella Preycineti (pi. cxviii. f. 19, 20), Recluz, 

 Rev. Zool. 1841, p. 375. 



N. testa ovali, convexa, sub epidermide angulatim lineata ; apice 

 magno, marginem superante; labio interno in medio producto, 

 uvulajformi, cmadrato ; impressionibus muscularibus latissimis. 



Resembling N. Suffreni, but having the septum still more 

 strongly uvulseforin and the produced part squared. The muscular 



4 b 2 



