THEBA CANTIANA. 81 
with fawn, and longitudinally streaked with white, due to the foldings of the inner 
wall being visible through the investing tissues ; the EPIPHALLUS is long, tapering, 
and naturally somewhat twisted at its origin, and is terminated by a short and 
abruptly flexed FLAGELLUM ; there is no penial retractor muscle. SPERMATHECA 
very large, subtriangular, and whitish-grey, its stem pearly-white, with frequently 
a double inflation ; a vaginal MUCUS GLAND is present at each side of the vagina, 
each with three to five vermiform, semitransparent opaline branches, resulting from 
two repeated bifureations; near the external aperture and opposite the penial 
opening there is a slender and tapering CCUM, 20 or more millimetres in length; 
this is probably an egersidium or excitatory organ, and represents and replaces the 
function of the lost dart; it is of an opaline azure colour at the slightly swollen end, 
the rest of the organ being pinkish-grey and minutely spotted. 
Moquin-Tandon is quite misleading in his description of the anatomy of this 
species, as he states that it does not possess any mucus vesicles ; but in British 
specimens there are two well-developed bundles, and Herr P. Hesse and A. Schmidt 
concur in attributing similar organs to continental specimens. 
Moquin-Tandon would also seem to be quite unaware of the presence of the 
conspicuous blind ezecum opening into the vestibule, which is here assumed to be a 
modified vestige of the dart-sac formerly present. 
The ALIMENTARY ORGANS are of the usual character, and present a whitish or 
yellowish G@sOPHAGUS, which shows a series of longitudinal white streaks due to 
the foldings of the inner walls being visible through the investing membrane ; the 
SALIVARY GLANDS are 6-8 mill. long, slender and whitish, fused together in their 
upper half, the ducts being about equal in length to the gland itself ; the STOMACH 
is thin and capacious, of a dusky-grey colour, and elbowed at the further extremity, 
where it receives the two biliary ducts, which also bind the stomach to the diges- 
tive gland; the INTESTINAL CANAL is of the usual triodromous character, and of 
a dull green, usually paler than the ordinarily dark greenish-sepia of the liver; 
on leaving the stomach the first intestinal tract takes a downward course and is 
fixed to the integument, beneath the kidney, it then returns beneath the head of 
the kidney towards the stomach, before reaching which organ it again flexes and 
passes through the liver and gradually narrows to the anal opening. 
The JAW or mandible is only slightly crescentic in shape, and quite narrow, with 
bluntly-rounded ends, of a deep brown colour, 
especially at the thickened cutting-edge, be- 
coming of an amber tint towards the thinner 
upper margin, and bears on its anterior sur- 
face eighteen or more somewhat irregularly 
distributed flat ribs, which are narrowest and 
most crowded in the centre and widest to- 
wards the extremities, where they are some- Fic. Bicalew of eae cantions Mout 
what convergent in an upward direction ; the EL re. De Mr. J een Sp 
lower or cutting margin is feebly denticulate 
or undulate by the projection of the flattened ribs, and the centre shows a feebly 
indicated, blunt, median rostrum. 
The RADULA is oblong in shape, about 44 mill. long and 2 mill. broad, and 
composed on the average of about 135 curved transverse rows of teeth, each row 
containing about 83 teeth, constituted by a median row of tricuspidate teeth, 
characterized by a long and powerful mesocone, whose cutting-point extends beyond 
| at 
KEOORGQ 
Fic. 118.—Representative teeth from half a transverse row of the radula of 7heba cantiana (Mont.), 
photographed by Mr. W. Bagshaw from a preparation by the late Mr. J. W. Neville (highly magnified). 
the basal-plate, and with a fairly developed ectocone on each side. The admedians 
or laterals are about fifteen in number, bicuspidate in character, possessing a 
strong and stout mesocone, and an ectocone which, as is usual, tends to become 
more developed as the teeth recede from the centre. The marginals are about 
31/8/17 Bi 
