336 PROCEEDINGS OF THE ACADEMY OF [May, 
Holospira bilamellata Dall. Plate VII, figs. 1 to 1d. 
Holospira (Distomospira) bilamellata Dall., Proc. U.S. Nat. Mus., XVIII, 
1895, p. 4; XIX, p. 896, p. 349, Pl. 31, fig. 3.. Pilsbry, Man. of Conch., 
XV, 1902, p. 82, Pl. 16, figs. 5, 10, 11. Bartsch, Proc. U.S. Nat. Mus. 
XXXI, 1906, p. 134. Daniels, Nautilus, XX VI, p. 41, Pl. 5, fig. 9 (normal) 
and fig. 8 (abnormal) shells. 
The first four references cited above pertain to specimens of the 
original lot, of which there are 8 perfect shells in Coll. U.S. Nat. Mus. 
and 22in Coll. A. N.S. Phila: 
The species is distinguished from H. crossei chiefly by its greater 
size. It was found by Mr. Daniels and the writer in great abundance 
at Station 5, on the east side of Daniels Mountain under the cliffs 
close to the summit, with Ashmunella mearnsi and Oreohelix, in the 
pimon zone. In most of the shells the external ribs weaken or dis- 
appear on the penultimate and one or two earlier whorls, but in 
some they continue to the last, as in the type lot of bilamellata. 
Sixty examples from Station 5 opened, most of them measured 
give the following data: 
(1) One lamella, the axial. 13 specimens = 213%. 
Length 23, diam. 5 mm.; whorls 19 
oe 2 ce ce 
ae 183 
ce 19.5 cc 5 cc ce 163 
cc 19 ce ANT cc 3 17 
7s 18 “ce 5 ce cc 16 
“cc 18 zs 5 ce a3 16 
ee EH re ne fa eg Bie ec 
DN ML Te nck, aaa i eLO 
“e 16 ce 4.5 oe as 143 
fy llc Oiaie ci  UOIS k Pe aries 
(2) Two lamelle, axial and basal. 41 specimens = 682%. 
Length 2.2, diam. 4.9 mm.; whorls 183 
ce AN) iz (a9 iz 
163 
cc 20 a9 49 a3 ce 163 
6 O Oerse es ALB i es 
“c 19 ce 5 6é a3 16 
a3 19 ce 5 igs (as 153 
ce 19 ce 5 cc cc 163 
<3 SSB wa eye dG “163 
“ 19 z3 5 ce a3 117 
“cc 18.6 “ee 5 ce ce 153 
“cc 18.5 cc 5 ce ims 153 
ce 18.2 “c 5 ce cc 163 
fe BIDS ay WEAR Ae i Jae 
“ Le ce 5 ce cc ie 
ac 18 ce 5. 73 iz 153 
