304 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



EEMARKS ON THE SHELLS OF THE GENUS RHOLEA, WITH 

 DESCRIPTIONS OF TWO NEW SPECIES FROM SOUTH 

 AMERICA, AND THE DESCRIPTION OF PAFUINA CHILO- 

 GRROA, N.sp., FROM BRITISH NEW GUINEA. 



By S. I. Da Costa. 



Read 14th April, 1899. 



Up to tlie present only three species of tlie singular and interesting 

 genus Hhodea have been described, all from the north-western portion 

 of South America, and all admirably figured in the Journal de 

 Conchyliologie for 1876, pp. 5-24, pi. i, figs. 1-3. The peculiarities 

 of the shells of this genus lie principally in the remarkable triangular 

 mouth, the excavation of the base, and the spiral columellar fold 

 •which ascends to the very apex, as shown in Figs. I and II of prepared 

 specimens of R. gigantea, Mouss. During the preparation of the adult 

 specimen, nine embryonic shells fell out, thus showing the animal to be 

 viviparous, and a tenth young shell was found adhering to the parent, 

 about a third of the way up the outside. Another peculiarity about 

 the shells of this genus is, that in some species they are dextral, in 

 others sinistral, whilst in one about to be described both dextral and 

 sinistral examples occur. 



GrENirs Ehodea. 



1. Ehodea gigantea, Mouss. : Pfr., JS'ov. Conch., iv, p. 119, 

 pi. cxxvii, figs. 10, 11. Shell dextral. 



2. E. Wallisiana, Dohm : Jahrb. Deutsch. Malak. Ges., vol. ii, 

 p. 307, pi. X, figs. 7, 8. Shell sinistral. 



3. E. Pfeifferi, Crosse: Joum. de Conch., 1876, p. 14, pi. i, 

 figs. 1-1 h. Shell dextral. 



4. Ehodea ^quatoeia, n.sp. Figs. Ill and IV. 



Testa elongata, cylindracea, vel dextrorsa vel sinistrorsa, sordide 

 albida, epidermide lutescente plus minus induta ; spira cylindi'acea, 

 superne sensim angustata, ad apicem obtusiuscula ; anfractus 13, 

 superiores quinque convexiusculi, sex sequentes planati, duo ultimi 

 concavi, ad suturam acute et prominente carinati, oblique arcuatim 

 striati, ultimus ad peripheriam carinatus, infra carinam radiatim 

 striatus, planus ; apertura — ? (fracta) ; columella arcuata, spiraliter 

 Yolvens, umbilicum cavum formans. Long. 23, diam. 4'5 mm. 



Sah.- — Paramba, Ecuador. 



Prom the imperfect condition of the apertures of these shells it is 

 impossible to ascertain the exact form of the mouth, but from their 

 general aspect it is probable this is similar to that of Rhodea Wallisiana, 

 Dohrn, which, however, is a somewhat larger species. Two specimens 



