™ 
250 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 
had the opportunity of observing: the season also exercises som 
influence. My specimens were collected during winter and in th 
early spring. One living specimen measured 35mm. in length | 
5mm. in breadth. 
The dimensions of a good-sized spirit specimen are :— 
1. Length over back from head to tip of tail, 83 mm. 
. Length of sole, 81mm. 
. Width of back, 15 mm. 
. Breadth of sole, 5mm. 
Breadth of groove between sole and back, 2°5 mm. 
Distance of anus from right tentacle, 6°56 mm. 
Distance of anus from pulmonary orifice, 5mm. 
Distance of pulmonary orifice from head, 11mm. 

vi IV. Vill. IX. 
Athoracophorus dubius (Ckll.). 
III. Anterior portion of genitalia: magnified. IV. Internal wall of penis, show 
papille: magnified. V. Papille of penis wall: greatly magnified. VI. Cem 
tooth of radula, x 720. VII. Sixth tooth of radula, x 720. VIII. J 
x 15. IX. Digestive system, enlarged. 
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LETTERING OF THE FIGURES. 
alb.gl. albumen gland. v.d. vas deferens. 
h.d. hermaphrodite duct. Bm. buccal mass. 
h.gl. hermaphrodite gland. s.e. salivary glands. 
ov. oviduct. cesophagus. 
ov’. free oviduct. c. crop. 
pr. _ prostate. St. position of stomach. 
p- penis. i liver. 
r.m. retractor muscle. I. intestine. 
r.s. _ receptaculum seminis. i. rectum. 
v. vestibule. 
