OF CONCUOLOGY. 201 



15. Partula bilineata, Pse. 



Description. — T. conico-ovata, solida, nitida, umbilicata, 

 transversim tenui striata; anfr. 5, sutura vix impressa; aper- 

 tura ovalis, verticalis, forte dentata, ad basin rotundata ; labro 

 incrassato, subano-ulato, intus calloso ; columella callosa. 



Fulvescente cornea, fasciis duabus rufescente fuscis, rarissime 

 fascia lata unica cingulata. 



Dimensions. — Long. 18, diam. 12 mill. 



Shell conically ovate, solid, shining, umbilicate, transversely 

 finely striate; whorls 5, suture somewhat impressed; aperture 

 oval, vertical, strongly dentate, rounded at base ; lip much 

 thickened, very slightly angulate near its outer edge, within 

 callous ; columella callous above. 



Yellowish horn color, with two reddish-brown bands or 

 lines, or very rarely with one very broad band occupying the 

 greater part of the whorl. 



Observations. — The four previous species have been referred 

 to P. auriculata, Brod., which was collected by Mr. Cuming at 

 the Tahitian Islands, and described by Mr. Broderip in Proc. 

 Zool. Soc, 1832. The local^ given, Huaheine, is incorrect. 

 Our collection from that island is very large, comprising shells 

 from every valley, all of which are of one type, that repre- 

 sented by P. rosea, Brod., and are quite distinct from those 

 inhabiting the other islands of the group. The species of 

 strictly auriculate shape of aperture are confined to Raiatea 

 and the nearly-connected island called Tahaa. It is not im- 

 probable that Mr. Broderip had before him more than one 

 species when he drew up his description. The variety he 

 mentions is probably a ground species. 



All authors since have placed the auriculata as a variety of 

 P. Otaheitana, Brag. The nine figures given by Deshayes in 

 Ferrusac's large work, are all from species inhabiting the 

 island of Tahiti, and none of them approach P. auriculata. 



Figures 11a and lib, by Reeve, are undoubtedly from 

 Raiatea, and one of them should be retained as the auriculata. 

 Figure lie is crassilabris, nob., described above. It is a ter- 

 restrial species from Raiatea. Dr. Pfeiffer, in his first Mono- 

 graph, includes auriculata with Otaheitana, but in his last 

 omits it altogether. I would observe, that there is a very 

 rare dwarf variety of Otaheitana somewhat approaching the 

 latter figure by Reeve, but it is of the normal shape of that 

 species, and always sinistral. Figures 13a and 13b are from 

 the island of Tahiti. We have named it sinistrorsa, although 

 Mr. Cuming places it as a variety of rubescens, Rve. The lat- 

 ter species we consider the real type of Otaheitana. 



