548 



tim strigilata et reticulata; apice decumbente, longe marginem 

 posticum superante; labio interno latiusciilo, margine arcuato; 

 operculo subelongato^ deiite eloiigato. 



More elongated than N. depressa, and having the apex pro- 

 duced very much beyond the margin; the septum is rather 

 broader and arched at the edge ; the operculum is rather longer. 



Lebouka, Feejee Islands. 31. Faroes. 



3. Navicella Luzonica (pi. cxvii. f. 6, 7), Recluz, Eev. 

 ZooL 1841, p. 376. 



N. testa oblonga, valide convexa, immaculata; apice decuiu- 

 bente, longe marginem posticum superante; labio interno lato, 

 margine recto. 



Oblong, and with a large apex as in N. macrocephala, but much 

 more convex and destitute of markings, and the septum nearly 

 straight at the edge. 



Island of Luzon; Souleyet. On stones in rivers; Islands of 

 Panay and Mindinao, PhiHppines ; Cuming. 



4. Navicella depressa (pi. cxvii. f. 8, 9, 10), Lesson, Voy. 

 de la Coquille, p. 368. Var. N. zebra. Lesson. 



N. testa ovali, depressa, sub epidermide nigro divaricatim stri- 

 gilata; apice recto, marginem tegente; labio interno subangus- 

 tato, margine recto ; operculo subquadrato, brevi. 



Although the convex side of this species is much less elevated 

 than in N.porcellana, and the apex less prominent, I have much 

 hesitation in admitting the validity of the distinction. 



New Guinea, New Holland, New Ireland ; Quoy et Gaimard. 

 Tahiti ; Cuming. 



5. Navicella Janellii (pi. cxvii. f. 11, 12, 13), Recluz, 

 Kev. Zool. 1841, p. 376. 



N. testa ovali, valide convexa, minute concentrice striata, 

 sub epidermide nigro lineata et reticulata ; apice oblongo, vahdo, 

 marginem superante ; labio interno lato, plerumque aui'antio, in 

 medio paululimi arcuato; operculo magno, griseo, prope dentem 

 angulariter emarginato. 



Differing from N.porcellana in having the apex more distinct, 

 and decidedly curved upwards (holding the shell in a position ana- 

 logous to that of a Nerita with the spire uppermost) . The septum 

 is also broader than in N. porcellana, and slightly arched in the 



