104 PROCEEDINGS OF THE ACADEMY OF [Feb., 
to an irregular costulation. There is an angular gutter behind the 
basal lip, and the reddish-brown color gives place there to a wide 
buff stripe which borders the lip. The whole base has a sculpture of 
extremely minute spiral lines in fresh examples; and under the micro- 
scope a very minute spiral lineolation is seen between these spiral 
lines, which are readily visible with a hand lens. The upper surface 
also shows very faint spiral lines in places, and there is often some 
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Fig. 19.—Ashmunella f. albicauda P. and F. A-C, from Box’of White Tail 
(diam. 13.3mm.); D, Station 14 (diam. 7 mm.); E, Station 2 (diam. 12 myn.); 
F, Station 14. 
> 
interruption of the growth strie, giving a slight appearance of puncta- 
tion. Seven specimens from Station 14 measure: 
Alte, Sve smear butts 5 Buh. Bab... 4%. * 6.2 AS 
UD o deel ee: 12.5; A235. 42 11.5; D155 . das ee eee 
WIIG; ack te t.c oo ee 54 54 54 54 54 54 54 
While variable in size and elevation of the spire, which may be nearly 
flat or low-conic, and in the shape of the basal teeth, the variations 
do not seem to differ in the several colonies. 
Terminal ducts of the genitalia are figured on p. 95, fig. 16, and 
the measurements are given in the table, p. 97. The epiphallus in the 
individual measured (No. 97,939, Station 4, in White Tail Canyon) is 
