173 SCINTILLA. 



4. Sc. ambigua (f. 1, 2, 3, 4). — Testa pallido aurantia, tenui, 

 oblonga, depresso punctulato, prismatica, subdiaphana, subin- 

 flatS ; latere antico subtruncato, postieo rotundato, majore ; margine 

 ventrali liiatu mediocri; dcntc antico in valva sinistra bifida. 

 Obs. Tlie substance of this shell is so far diaphanous that the 

 muscular impressions can be seen on the outside. The veutral 

 opening is not large. 



5. Sc. auuantiaca (f. 5), Desk. — Testa aurantia, quara Sc. am- 

 bigua uiagis elongata ; hiatu parvo. Obs. The narrowness of this 

 shell is hardly sufficient to distinguish it from the preceding. 

 The hiatus is, however, smaller. 



6. Sc. pallidula (f. 6), DesA.— Testa pallida, Sc. ambigua 

 simili, sed margine ventrali vix hiante. Obs. The very small ven- 

 tral opening is the principal difference between this and Sc. 

 ambigua. 



7. Sc. Forbesii (f. 7, 8), Desk. — Testa inflata, ovali, pallide 

 aurantia; latere antico paululura breviore ; subtruncato margine 

 ventrali arcuato, vix hiante. Obs. A little more regularly oval, 

 and a little more equilateral than Sc. ambigua. 



8. Sc. Bouneensis (f. 10), Desk. — Testa albida, concentrice 

 substriata, subinflata, latere postieo majore, latere antico oblique 

 subtruncato ; margine ventrali subcontracto. Obs. Like Sc. 

 Adamsii, but more inflated, slightly contracted at the ventral edge, 

 and faintly striated or undulated concentrically on the surface. 



9. Sc. rosea (f. 11), Desk. — Testa rosea, polita, inflata, clausa, 

 oblonga ; latere postieo lougiore et latiore, latere antico parvo, 

 declivi. Obs. Of a beautiful rose tint; this shell is also remark- 

 able for the smallness of its anterior as compared with its poste- 

 rior side. 



10. Sc. pudica (f. 12), Desk. — Testa Sc. rosea simili, sed 

 latere antico subquadrato ; margine ventrali paululura aperto. 

 Obs. More square and truncated than 6c. rosea, with a very slight 

 opening in the ventral margin. 



11. Sc. Recluziana (f. 13). Desk. — Testa tenui, rosea -purpu- 

 rescente, oblonga, latere antico truncato ; margine ventrali recto, 

 clauso. Obs. A thinner and more purple shell, more straight at 

 the ventral margin and truncated on the anterior side than Sc. 

 ptulica. 



