THE NAUTILUS. 67 



The species has apparently heretofore been mistaken for 0. rosn- 

 lina, although the one is quite distinct from the other, especially so 

 in general form, number of spiral whorls, and the non-appearance 

 in 0. Blanesi of the rose colored base of the columella, which is sel- 

 dom if ever absent in 0. rosalina. 



A fine suite of these shells has been in my collection for several 

 years, unnamed. Though convinced that they were an undescribed 

 species they remained neglected until I recently found in the fine 

 collection of Mr. Francisco E. Blanes, late of Cuba, a large number 

 of the same form mistakenly labelled 0. rosalina Duclos. All, or 

 nearly all of this entire lot had been collected by himself near Car- 

 denas, Cuba. A brief explanation and comparison with genuine 0. 

 rosalina was sufficient to satisfy him of their distinct character, and 

 the result is the new name, Olivella Blanesi. 



Specimens entirely white, secured at the same locality might well 

 be termed var. alba. Some suspicion that these colorless shells 

 might be identical with 0. pura or 0. bullula as figured by Reeve 

 being felt, specimens were submitted by a friend to Mr. E. R. Sykes 

 of London for comparison with Reeve's types. To his kind assist- 

 ance the following report is due: "I have compared your Olivella 

 (with Mr. Smith's ever ready helping hand). It does not seem to 

 be either pur a or bullula. Pura may not be the actual type, as it is 

 recorded by Reeve as in ' Mus. Metcalfe.' It is much more drawn out 

 than your shell. The one specimen is in pretty good condition and 

 seems never to have had much color marking, certainly not like 

 yours. 0. bullula here is snow white, but is thin and worn, so may 

 have had some color. It is slightly more elongate and does not show 

 the sinus that your species has in the columella. Very probably 



vours is new." 



A figure will be given later. 



AN INTERROGATION IN REGARD TO SEPTIFER BIFURCATUS RVE., 

 AND MYTILUS BIFURCATUS CONR. 



BY MRS. M. BURTON WILLIAMSON. 



Shells that vary from the type sometimes raise a question in re- 

 gard to the stability of their specific or generic values. Typical 

 shells of Septifer bifurcatus Rve. and Mytilus bifurcatus Conr. are 



