HOLOSPIRA. 79 



cord-like. The third lamella, running on the inside of the 

 outer wall of the penultimate whorl, is a rather low, narrow 

 and short callus, showing through distinctly from the out- 

 side. All three lamellae are glossy white (fig. 36). Strebel 

 gives the length of a specimen from Cuming as 15.7 mm., 

 whorls 16. 



Von Martens remarks that the specimen taken by Uhde ' ' is 

 very much shorter (length 12 mm.) than that of Cuming, and 

 it has only 14 instead of 15-16 whorls ; but in the diameter of 

 the whole shell and in the size of the aperture they are alike. 

 All are probably from central Mexico. ' ' 



5. H. NELSONI Pilsbry, n. sp. PL 22, figs. 42, 43, 44. 



Shell rimate, cylindric-tapering, the cylindric lower portion 

 passing imperceptibly into the tapering upper half; thin but 

 moderately solid ; white, more or less extensively stained with 

 blue, and with streaks and dots of blue or dark flesh- color, the 

 intervals between the white riblets on the base and several 

 early whorls being brownish flesh-colored. Whorls 15!/2> the 

 first two smooth, following 5 or 6 closely and sharply striated 

 obliquely, this sculpture then becoming more obtuse, chang- 

 ing to very low, rather coarse riblets, more or less obsolete in 

 places, and usually so in the middle of each whorl ; on the last 

 whorl these riblets become narrower, stronger and closer, on 

 its latter half still closer and sharper; and they extend over 

 the convex basal. The last whorl is very shortly produced 

 forward, flattened above, angular outwardly. Aperture ver- 

 tical, obliquely rounded-piriform, contracted and angular at 

 the upper external extremity, the margins straightened on 

 each side of the angle, elsewhere arcuate; peristome white, 

 expanded and somewhat thickened. Interior brown. Inter- 

 nal pillar small, of about equal size above and below, the 

 lumen of the penultimate whorl contracted by four lamellae: 

 a strong, thick-edged axial lamella, not over one whorl long, 

 and barely entering the last whorl; a larger lamella on the 

 parietal wall, arising rather suddenly and decreasing gradu- 

 ally, nearly one whorl in length, about half of this being in the 

 antepenult, whorl ; a low palatal fold about % whorl long on 



