MUSEUM OF COMPAKATIVE ZOOLOGY. 95 



Actseon incisus n. a. 



Shell short, thin, inflated, waxen white, polished, with five or six whorls 

 and a rather acute spire ; nucleus ndnute, more or less immersed, eroded to 

 some extent in every specimen ; apical whorls smooth, polished, rounded ; 

 suture very distinct, in the majority of cases not channelled ; the apical whorls 

 with two or three distant narrow grooves across which, in some cases, pass 

 elevated lines of growth which appear nowhere else, or, if at all, oidy in the 

 suture near the apex ; last whorl forming the largest part of the shell, inflated, 

 provided with ten or eleven spiral grooves, which, are nearer together ante- 

 riorly ; these grooves are somewhat zigzag by exigencies of growth, but are not 

 punctate, as in so many species ; other spiral sculpture consisting of micro- 

 scopically fine slightly zigzag striae, about seventy in the width of a millime- 

 ter ; transverse sculpture only of most delicate flexuous lines of growth most 

 evident near the sutures ; aperture rounded in front, pointed behind ; outer 

 lip thin, simple, arcuated toward the periphery, passing imperceptibly into the 

 pillar ; body with a slight callus j oining the rather slender pillar which carries 

 one inconspicuous fold. Lon. of shell, 9.0 ; of last whorl, 7.0 ; of aperture, 

 5.75. Max. lat. of shell, 5.75 ; of aperture, 3.0 mm. 



Yucatan Strait, 640 fms. ; ofl" Cape San Antonio, 640 fms. 



A peculiarly thin delicate polished and inflated species. 



Actaeon melampoides n. s. 



Shell short, stout, with a depressed spire and shouldered last whorl ; white, 

 with ftve whorls, sculptured *with punctate spiral lines ; nucleus small, 

 eroded ; other whorls with two, three, or (on the last) twenty to twenty-five 

 spiral lines, which are distinctly punctate, with about ten punctations in the 

 length of a millimeter ; the spirals are crowded just in advance of the suture 

 and near the pillar, and especially distant on the shoulder of the last whorl ; 

 suture distinct, with the anterior margin finely crenulate in the last w^horl ; 

 other sculpture of fine lines of growth and microscopic revolving striae as in 

 the last species ; outer lip hardly oblique, joining the body at a wider angle 

 than usual, owing to the shouldering of the last whorl, thin, simple, passing 

 imperceptibly into the short, twisted pillar, which bears a single distinct fold ; 

 body wliorl with only a glaze, pillar hardly or not at all thickened ; aperture 

 approximately lunate. Lon. of shell, 6.0 ; of last whorl, 5.25 ; of aperture, 

 4.25. Max. lat. of shell, 4.0 ; of aperture, 1.62 mm. 



Station 19, 310 fms. 



This species has a good deal the outline of the common Melampus corneus 

 of the cast coast of America. 



