50 YOLVARIA. 



M. MEXICANA, Jousseaume. PI. 13, fig. 1. 

 Rather solid, opaque white, with four very obscure bands, 



columelia four-plaited. Length, 7 mill. 



Mexico . 



Possibly a variety of M. lactea, Kiener. I am not acquainted 

 with the species. 



M. A VENA, Valenc. PL 13, figs. 2-5, 8. 



White or yellowish white, with three broad bands of brownish 



yellow ; columelia four-plaited. Length, '45-'6 inch. 



West Indies. 

 Var. BEYERLEANA, Bernardi (figs. 3, 8). 



White or rosy-white, with the bands of rose-color ; it is clearly 

 connected by intermediate shades with the type. Some of these 

 intermediate states are M. livida, Reeve (fig. 4), M. ejfulgens, 

 Reeve, and M. gu Mulct, Reeve (fig. 5 . 



Var. AVENELLA, Dall. 



Shell exceedingly variable in proportions ; spire short, obtuse, 

 sometimes almost suppressed ; color light yellow or yellowish 

 white, with a faint white 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 

 termination; columelia 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 - and 9*5; of 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, TO and TO mm. 

 Off Cape 8an Antonio, 1002 fins.; Station 5, 229 and 



152 fms ; Station 2, 805 f thorns, Guiibbrnn. 



