62 LAND AND FRESHWATER 
Revue et Mag. Zoologie, January, p. 53 (1867); Lovell Reeve, Land 
& Freshwater Moll, British Isles, p. 13 (1863); J. Mabille, Annales 
de Malac. p. 120 (1870). 
Loc. An island in Dingle Bay, west coast of Ireland. Coll. Brit. 
Mus. 
Shell (Pl. XII. fig. 2) covered on the outside with a very thin trans- 
parent epidermis. The mucous gland is very small (figs. 1, 1a), the 
pedal margin of the foot very distinct and similar to that of Arion. 
The renal organ is triangular in form, its nearly equal sides completely 
surrounding the heart (fig. 8), which is thus central as regards that 
organ, as in Arion (fig. 9); but in that genus the form of the renal 
organ is lunate. The ventricle is directed towards and very close to 
the anal and respiratory orifices, while in Arion it is more remote 
and in a more posterior position. These differences in position and 
form of the renal organ in this genus, Arion, Anadenus, and Limax 
are shown in fig. 10, where it lies alongside the heart and posterior 
to it. 
Retractor muscles. Those of the two eye-tentacles (7.m.7., fig. 8) 
are attached at the right and left posterior margin of the mantle, 
that of the odontophore or buccal mass (7.m.0.) just behind the 
attachment of the right eye-tentacle; while that of the penis is 
situated far back near the extremity of the foot on the left posterior 
side. Nowin Arion the attachments of the eye-tentacles and odon- 
tophore are closer together at the posterior margin of the mantle, 
and that of the penis is here also occupying a middle position be- 
tween the muscles of the eye-tentacles. 
If we examine Limax again (fig. 10) we find a still greater 
divergence. The retractor muscle of the penis (7.m.P.) is anterior, 
on the mantle-margin, and that of the eye-tentacles and buccal 
mass (rm. O., Ey, T.) are all close together on the posterior right 
margin. 
Odontophore. The jaw is distinctly ribbed, solid, dark brown in 
colour; concave in front, with a sharp edge. The dental formula is 
59 . 1.59. 
The central tooth is unicuspid, rather short and broad; the median 
teeth are long, sharply pointed, with a very small notch or cusp at 
the outer basal margin. This becomes better developed in the lateral 
teeth; up to the 14th or 15th median the teeth are uniform in 
size, but they then become gradually smaller towards the sides, and 
about the 46th are much broader at the base, with the outer tooth 
well developed ; the last five or six are very minute, and the cusps 
blunt and irregular. In the form of these laterals and the radula 
generally it has a most interesting similarity to that of Anadenus, ° 
which also has a ribbed jaw. It is quite unlike Arion in this 
character of the radula. In one specimen the teeth were quite 
worn down in the centre, so that the points were reduced to a 
blunt knob. The stomach of this individual contained a consider- 
able quantity of coarse angular sand mixed with the food, which 
appeared derived from granite rocks. 
Generative organs. I have dissected two specimens, and both 
