66 QUEENSLAND AGRICULTURAL JOURNAL. [1 Jury, 1899. 
narrowed both forwards and backwards, the front and hind extremities being 
rounded and projecting both over the head as well as the tail end. The upper 
surface has a uniform contour, and is gently convex from side to side, and slopes 
downwards also to both the fore and hind end. It isalso of a dull aspect, though 
moist, no mucous being poured out as in ordinary slugs. It is, moreover, com- 
letely occupied by fine granules and intervening pores. It is known as the mantle, 
its front are two pairs of tentacles arising from the head. The upper pair are 
stout, finely ringed, and end in a knob containing a minute eye spot. Beneath 
these are two, even stouter ones; these are much shorter than the preceding, 
and are terminally cleft, or each ends in two distinct tubercles. The under 
surface, which is lighter coloured than the upper, is almost quite flat, and is 
divided into three distinct portions, each extending the length of the slug. The 
central of these is the so-called foot, and that on each side is the under 
portion of the mantle. These three divisions may be equal in width, 
or the foot may be less than a third of the breadth. This foot has 
a more glossy lustre than has the remaining portion of the flat under 
surface, owing to the presence of mucous. It is also crossed by closely 
placed very fine lines or strie. The head may be withdrawn to a greater or less 
extent into a cavity. The mouth organs include the ordinary jawandradula. The 
former is arched and longitudinally folded, whilst the latter carries longitudinal 
series of cusp-bearing teeth. The male genital orifice is just behind the right 
lower tentacle, whereas the female one is at the side beneath, near the right border 
of the foot, not far from the middle of its length. The animal has the two 
sexes combined in one individual. The adults in both species measure 8 inches 
in length as ordinarily extended during crawling.* They may be distinguished 
one from the other by the following characters :-— 
Vaginula Leydigi, Simroth, when fully developed, is pitchy-brown or 
almost black above, and there extends along the centre of the back a fine yellowish 
line, which does not quite reach either end. The back also is gently and regularly 
curved from one side to the other. The under surface is of a brownish-white 
colour, the foot having a slight yellowish hue. The latter, extending from one 
end to the other, occupies about a third of the breadth. 
When young the animal is of a much lighter colour, it being usually pale- 
brown, with numerous dark-brown specks above, these often forming an obscure 
network. Beneath it is greyish-white. 
The eggs are soft, translucent, oval, slightly flattened at one extremity, 
about twice as long as broad, and of a honey-yellow colour. These appearances 
being partly due to the nature and form of their contents: for they are 
surrounded by a thick transparent colourless covering that presents at one 
extremity a short thick blunt prolongation. They are large, measuring 8 mm. 
(4 lines) x 4 mm. (2 lines). 
Vaginula Hedleyi, Simroth.—This species is of a pale yellowish-brown or 
drab colour above. ‘The upper surface also is not as convex as is the back of V7, 
Leydigi, and not so uniformly arched from side to side, being somewhat flattened 
towards each lateral border. Beneath it is brownish-white. The central area or 
foot does not occupy a third of the breadth, but only two-thirds or less thereof. 
_ The eggs are generally similar in appearance to those of the preceding 
species, but are distinctly smaller, measuring 6°5 mm. (3 lines) x 3°5 mm, 
(1# lines). ; 
A close insight into the anatomy of these two species, as Dr. Simroth hag 
remarked, reveals a surprising amount of difference also in the form of almost 
all their internal organs. For an indication of the nature of this—which is 
beyond the scope of this article to describe—reference must be made to either 
of the two memoirs that have emanated from him, and that have been already 
alluded to (page 64). It must be understood, however, that it is in these 
structural details that the characteristic features of the two species reside. 
~ peaerely speaking, they may be stated to resemble the slug-like mollusc of such frequent 
oceurrence under logs and stones in mangrove swamps, and which are referable to the genus 
Maas much so indeed that earlier writers, ¢.g., Guilding, confounded the two under this 
one title, ; 
