•380 PROCEEDIXfiS OF THE XATIONAL MUSEUM. vol. xxx. 



iviulci- the Hattened and faintly spirally striated, raised spaces between 

 the incised channels feebly crenulated on both edges. Five incised 

 channels api)ear between the sutures on the second and third whor! 

 and six on the fourth and fifth. Periphery and base of the last whorl 

 well rounded, the latter sculptured like the space between the sutures, 

 with six spiral channels. Aperture quite large, suboval, postei'ior 

 angle o])tuse, outer lip thin, denticulate. The incised spiral channels 

 appear as a chain of squarish areolations within, by transmitted light; 

 columella moderately strong, somewhat twisted and slightly reflected 

 with a subobsolete oblique fold near its insertion; parietal wall cov^- 

 ered by a very feeble callus. 



The specimen descrihc^l })elongs to the Pa?tel collection. It is from 

 Japan and has six and three-fourths post-nuclear whorls and measui'es: 

 long. 7 nun.: diam. 3.3 mm. 



PYRAMIDELLA ( ACTiEOPYRAMIS ) AMCENA A.Adams. 



Plate XIX, tig. 1. 

 Monoptygma amrena A. Ad.a.ms, I'roc-. Zool. 8oc., 1851, p. 22.S. 



Shell slender, elongate-conic, turrited, milk white. Nuclear whorls 

 small, almost completely immersed in the first of the later whorls, the 

 peripheral portion of the last volution only is visible, which shows 

 that the axis of the nucleus is at right angles to the axis of the later 

 whorls. Post-nuclear whorls very high between the sutures, decidedly 

 shouldered, moderately w(dl rounded, marked by rather coarse lines of 

 growth and deeply incised spiral chaimels, which are crossed by many 

 regular, (juite well-developed, axial riblets. These little riblets divide 

 the channels into regular chains of pits. There are live channels 

 l)et\vecn the sutures on the second and third whorl and six on the 

 following three. The raised portion between the channels is of about 

 double the width of the channel, somewhat crenulated on both margins 

 and faintly spirally striated. Periphery and base of last whorl well 

 rounded, sculptured like the space between the sutures, with nine 

 spiral channels, the raised spaces between them gradually diminishing 

 in breadth toward the lunbilical region, which is somewhat excavated. 

 Aperture subquadrate, posterior angle acute, junction of columella 

 and outer lip subchanneled; outer lip somewhat expanded at the outer 

 edge, wavy in outline, rather thick, the incised channels appearing as 

 mere lines within by transmitted light; columella straight, thin, fold 

 not visible in the aperture; parietal wall without callus. 



Two specimens are among the Berlin material-, both in the Patel 

 collection and from Japan, The larger one. descril)ed above, has seven 

 post-nuclear whorls, and measures: long. 7 mm.; diau). 2.6 mm. The 

 smaller one, lal)eled pupoides A. Adams, has six i)()st-nuclear whorls, 

 and measures: long. 5.4 mm.; diam. 2.3 nun. 



This species recalls /-*. (.1.) hi,it<(, but is inu<-li more slender. 



