66 Panama Shells. 



PURPURID-B. 



ture ; last whorl spirally canaliculate on the left side : aper- 

 ture subelliptioal : labrum rather sharp, thickened by a broad 

 varix, coarsely grooved within ; labium well thickened, not 

 appressed, with two small wrinkles anteriorly : notch deep. 



It resembles N. versicolor (v. infri) var. striatula : but 

 besides being more coarsely striated and minutely ribbed, the 

 whorls are much more convex. 



Mean divergence about 48° ; length .58 inch; breadth .31 

 inch ; length of spire .33 inch. 



Station. — Unknown. 



Habitat.— Tahoga ; C. B. A. ! 

 2 specimens were obtained. 



55. IVassa versicolor. — Nov. sp. / 



Shell long ovate conic : pale yellowish brown, or nearly 

 white, with a darker sutural lino, or blackish brown : some- 

 times the ends or the summits of the ribs are whiter than the 

 interspaces ; sometimes the sutural fascia covers the anterior 

 part of the last whorl : with, on each whorl, nine or ten narrow 

 very prominent ribs; with very minute spiral striae, which 

 are nearly obsolete on the middle of the whorls ; spire with 

 the outlines nearly or quite rectilinear : apex acute : whorls 

 eight, slightly convex, with a well impressed suture ; last 

 whorl spirally canaliculate anteriorly : aperture subelliptioal : 

 labrum subacute, thickened with a stout varix : labium thick- 

 ened, not appressed, finely wrinkled : notch deep. Var. stria- 

 tula is covered with very distinct striec. 



Mean divergence about 45° ; length .6 inch ; breadth .33 

 inch ; length of spire .35 inch. 



N. ambigua, the Caribbean analogue, is also an extremely 

 variable species. 



Station. — Unknown. 



