1915.] NATURAL SCIENCES OF PHILADELPHIA. 343 
there is decidedly more vegetation. A few were picked up on the 
slope towards Station 10, dead shells being scattered all over the 
upper 500 ft. or more of this ascent. 
Sixty specimens were opened, measurements of 31 being given below. 
(1) No axial lamella, merely a callous or very inconspicuous node 
on the axis in the penultimate whorl. 15 individuals = 25%. 
Length 14, diam. 4 mm.; whorls 13; penult. whorl smooth. 
12. 8, 3.9 te 
aigte Oa 3. cae faye. Ma” Sasol eae ‘¢ weak ribs. 
Caan bk ee) 8 as See be we ‘* smooth. 
Be ve Se hes ae ete ee ‘“ strong ribs. 
series, ne es) A. . Peete 2 ee ‘weak ribs. 
ing 13; ce 3.7 ce (73 12 (73 ia§ (7 ce 
ad ee ee lpr Sw id IE ek ‘* smooth. 
ce 10.5; (73 3.8 as 73 te é (a9 (73 
(2) Axial lamella in penultimate whorl short and strong; no other 
lamellae. 30 individuals = 50%. 
Length 13, diam. 4 mm. ; ; whorls 123; penult. whorl weak ribs. 
12, 4 
COM £2: iG 3.8 e 66 12: oe 66 G a 
SP aS ERS tana oe Peale a ‘“ “smooth. 
ce 11.8, “cc 3.8 ce ce 113; ce ce ce 
“ 11:3; Ts 3.6 a3 6 12: c a3 73 
(a3 if 6“ 3.9 6c cc 114; 6c a 6“ 
FSR aor 10 ae (Vere “weak ribs. 
7 S/O OS Ra em es aoe De ‘““ smooth 
COUT Gia aig: te li «493, ‘strong ribs. 
6c 10.5, ce 2) (a3 “cc i: ce cc cc ce 
(3) Axial lamella short and strong or rarely weak; a basal lamella 
within last half of penultimate whorl. 12 specimens = 20%. 
Length 13, diam.4 mm.; ; Whorls 132; penult. whorl smooth. 
6c 1 
ib mb: a 123; . weak ribs. 
(a4 tt iz 3.8 73 a3 133; ce ce ce 
Ay la aa ao aaa psa 2 oa ‘smooth. 
“ec 12.5, iz 3.8 ce ce 12: 6 as ce 
rt SI ty RA ak Mae 19 eee We ole 2k ee ‘ strong ribs. 
cc UAE igs Bite cc cc 148 c¢ cc ce ce 
ed 13.9: eee ae “weak ribs. 
(4) Axial, basal and superior lamellee in the last half of penulti- 
mate whorl. 3 individuals = 5%. 
Length 14, diam. 4 mm. ; whorls 13; penult. whorl weak ribs. 
fiat re, MA 121: He ‘* strong ribs, 
“ne all DTW een aeaien od: La oy tel ee ‘* smooth. 
