MUSEUM OF COMPARATIVE ZOOLOGY. 73 



ened ; it is slightly but distinctly reflected, and the canal is slightly recurved. 

 Lon. of shell, 5.62 ; of last whorl, 5.0 ; of aperture, 4.0. Lat. of shell, 3.0 ; 

 of aperture, 1.37 mm. 

 Yucatan Strait, 640 fms. 



Marginella torticula n. s. 



Shell slender, shining, grayish waxen white, of about five whorls ; spire 

 roundly pointed, slender, covered in the adult with a complete coat of trans- 

 lucent glaze almost obscuring the sutures ; last whorl somewhat appressed 

 between the junction of the outer lip and the suture ; turns somewhat laxly 

 coiled ; surface perfectly smooth ; axis laterally curved, with the convexity to 

 the left, so that the spire and the canal both point to the right of a straight 

 line when the shell is in its natural position ; aperture long and narrow ; colu- 

 mella with four very oblique folds, of which the one behind the anterior fold 

 is a little the most prominent ; outer lip simple, not reflected, slightly thick- 

 ened, and produced posteriorly, inwardly convex and externally concave in cor- 

 respondence with the bent axis ; aperture widest anteriorly, making the canal 

 very open ; no callus on the body whorl, which is joined by the outer lip at 

 an exceedingly acute angle. Lon. of shell, 11.5 ; of last whorl, 9.75; of ap- 

 erture, 8.0. Max. lat. of shell, 3.75 ; medium lat. of aperture, 1 .0 mm. 



Station 5, Lat. 24° 15', Lon. 76° 49'.5, in 229 and 152 fms., soft coral ooze. 



The only shells normally arcuated in this manner which occur to me are 

 some species of Eulima. The twist gives the shell a very peculiar and highly 

 characteristic appearance. 



Marginella (avena Val. var. ?) avenella. 



Shell exceedingly variable in proportions ; spire short, obtuse, sometimes 

 almost suppressed ; color light yellow or yellowish white, with a faint wliite 

 line bordering the suture ; general outline elongated ovate ; aperture long, 

 narrow behind (where the outer lip is thickened and a little inflected), wider 

 in front (where it is thin) and a little flaring at its (widest) anterior termhia- 

 tion ; columella with four subequal folds, all rather oblique ; outer lip simple, 

 thickened behind, where the line of callus may extend to the suture or fall 

 considerably short of it ; slightly concave in the middle, where its edge is 

 even turned in a little ; scarcely, if at all, produced forward ; whorls not at all 

 or very slightly shouldered, three or four in number. In the form with the 

 short rounded spire, the outer lip is straight, not inflected, and more evenly 

 thickened along its whole length ; the anterior end of the aperture has the 

 outer lip obliquely cut off", and not flaring; the whole form is more evenly 

 ovate-cylindrical. The measurements of the long and short spired specimens 

 are respectively as follows : — Lon. of shell, 12.0 and 9.5 ; of last whorl, 10.25 

 and 9.0 ; of aperture, 9.5 and 8.25. Max. lat. of shell, 5.0 and 3.75 ; lat. of 

 aperture at middle part, 1.0 and 1.0 mm. 



