THEBA CARTUSIANA. 99 
egersidium ; the PENIS-SHEATH is oval in shape, with a peculiar twist at the distal 
end, which is continued as a moderately long and cylindrical epiphallus, and term- 
inated by a short flagellum ; the VAS DEFERENS is distinetly and strongly dilated 
at its junction with the distal end of the epiphallus. 
Moquin-Tandon’s description and figure of these organs differ from those here 
figured, showing a very long stem to the spermatheca, ‘and only a long vermiform 
vesicle to represent the devenerate dart-sac, ete., found in English’ specimens, 
leading to the belief that by some error the organs of the true ‘cartusiana have 
not been figured or deseribed, but possibly those of 7. cantiana or some allied form, 
unless the large South European shell should prove to be a distinct intermediate 
species. 
The figure of the genitalia reproduced by Simroth (Bronn’s Tier-reich, iii., f. 198) 
from Sehuberth is also more in accord with that of Moquin-Tandon than with those 
given herewith, but differ from that author’s and the annexed figures in shewing an 
excessively elongated free oviduct or vagina between the mucus glands and the 
assumed excitatory organ. 
The MANDIBLE or jaw is about 1°5 mill. from side 
to side, and °36 mill. from the lower or cutting-edge 
to the upper margin, of an amber colour, but darker 
brown towards the cutting-edge, somewhat flatly 
arcuate, with blunt rounded ends, and bearing about 
eighteen broad, flat and somewhat divergent ribs, Fic. 150.—Jaw of Theba car- 
fairly regularly disposed over the whole anterior sur- asiane Mull, Lewes Bee . 
face, and slightly denticulating the lower or cutting SA gh aay, ore 
margin, but ‘there is no perceptible trace of a median paration by Rev. F.. W. Bowell). 
rostr ation. 
The RADULA is of the usual oblong shape, about 3 mill. in length and 1 mill. in 
width, and resembles that of Zheba cantiana, except that the cusps of the marginal 
teeth are much more elongate in the present species. The organ is constituted by 
about 140 transverse rows of teeth, each row composed of about 71 teeth, arranged 
as usual in three series: the median, the admedian or laterals, and the marginals ; 
the lateral series blending with the marginal teeth. The median series is formed 
by a single longitudinal row of tricuspid teeth, each bearing a stout mesocone, 
RTA ture 
Fic. 151.—Representative teeth from half a transverse row of the radula of Theba cartusiana 
(Miill.) collected at Lewes, Sussex, by Mr. C. H. Morris, and photographed by Mr. W. Bagshaw, 
from a preparation by Rey. E. W. Bowell (highly magnified). 
with a distinct ectocone at each side; the admedians or laterals are about twelve 
in number, bicuspid in plan, and larger and stronger than the central row; the 
marginals are about twenty-three in number and generally bifid, the cusps tome 
long. and comparatively slender, but towards or at the margin of the membrane the 
ectocone may become bifid. 
The formula of an example from Lewes, collected by Mr. C. H. Morris, and 
photographed ph Mer. W. Bagshaw from a preparation by the Rev. E. W. Bow ell was 
F424 h4 42435 x 140 = 9,940 teeth. 
Sane ad Be ciggmente None is known of the amours 
of this species, or any details of the preliminary coquettings leading up to 
conjugation, but according to Bouchard-Chantereaux and others the egos 
are laid in April and 1 May, and specimens were also found in September 
at Dover by the Rev. Canon Horsley, full of eggs, apparently ripe for 
exclusion, so that it is probable that egg deposition is continued intermit- 
tently through the summer and autumn months. 
The eggs are globular and opaline, with a thin, membranous and slightly 
nacreous envelope; they are about 14 mill. in diameter, and therefore very 
large for the size of the animal and almost as large as those of 7. cantiana, 
