332 BULLETIN OF THE 



Pi/ramtdella varieijata Tryon, op. cit., p. 302; not of Carpenter or A. Adams. 

 Pyramidelia Candida Tryon, op. cit., pp. '602, 373 ; not of Morch or Meuschen. 



Habitat. Carolina coast southward to Florida and Cuba. St. Thomas, 

 Cuming. West Florida, low water, to 2 fms., in the sea-weed or on muddy 

 flats, Hemphill. 



The first person to observe this species was Conrad, in 1846, during his visit 

 to Tampa, where he found it living, rare, on the shores of the bay. He named, 

 but unfortunately did not describe it, though there is no doubt that his obser- 

 vations can apply only to this species. Subsequently, after being at first con- 

 founded with its precursor, the Pliocene P. arenosa Conrad, it was described 

 by Holmes from the Post Pliocene, its existence in a recent state being also 

 referred to. The differences between arenosa and crenulata lie chiefly in the 

 more elegant sculpturing and crenulation of arenosa. The differences in the 

 teeth and folds alluded to l)y Holmes are not constant. Subsequently, the living 

 shell was dredged by Stimpson, at Beaufort, N. C. 



The west coast representative of this species is P. conica C. B. Adams. A 

 pale rosy specimen, of this was apparently described a little later by A. Adams 

 under the name of Obeliscus hastatus. Another beautiful color variety of this 

 species is P. variegatus Cpr, (non. A. Adams). These have dark and light 

 varieties like the crenulata. All these and the next species have been lumped 

 together by Mr. Tryon under the name of P. conica C. B. Adams. They are 

 nearly related, but in my opinion distinct species. P. crenulatus has the two 

 anterior small plaits dark brown, even in its light colored varieties. In P. con- 

 ica they are always white like the large posterior plait, even in the darkest 

 specimens. It is possible that the original hastatus A. Adams may be distinct 

 from P. conicay but the specimens I have seen labelled hastata seemed to be 

 merely a pale pinkish slender variety of conica. The variegatus Cpr. is ele- 

 gantly marbled and mottled with brow^n, white, and pearl gray. There is 

 another very delicate Californian species belonging to the typical section of the 

 genus which does not seem to have been named. It is about 10.0 mm. long, 

 and 4.0 mm. wide; white, with numerous golden brown dotted or hairlike 

 spiral lines; a smooth or lightly spirally striate surface; moderately rounded 

 whorls, about nine in number, without the usually decollate nucleus; the su- 

 ture distinct but not channelled; the umbilicus reduced to a mere puncture or 

 even absent; the pillar with one large and two anterior small folds, more trans- 

 verse than in P. conica and stronger; fasciole obsolete; the outer lip sharp 

 with three or four lirse in the throat. This species, which stands about mid- 

 way between the two sections of the genus, was collected near the mouth of 

 the Colorado River, at the head of the Gulf of California, by Dr. E. Palmer, 

 and may be called P. auricoma. It is like P. monilifera on a much smaller 

 scale. 



Stimpson observed, and I have confirmed it, that the operculum of P. crenu- 

 lata is thin and corneous, with a reniform outline. It consists of about two 

 turns, the spiral part being very minute and within the margin. It has a 



