CATHYPNADA. 95 
with two equidistant incisions, at each of which appears a bristle (fig. 4). The rotating 
cilia are set along the edge. A mastax of very ample dimensions, with a pair of long 
mallei, but rather small incus, is always conspicuous. Behind this the occipital brain 
carries an eye, usually large and brilliant. <A great saccate stomach, without sensible 
cesophagus, with large gastric glands, and followed by a separate intestine, passes 
obliquely across the dorsal region; and the ovary, as usual, occupies the ventral.! In 
the adult, the surface of the lorica is smooth, and the whole animal is transparent and 
colourless. 
Though individuals swim actively now and then, yet the habitual sluggishness and 
inertia of the species cannot fail to attract attention. As described, it will balance 
itself, by the hour, on its united toe-tips, with an occasional lazy swaying to and fro; 
or even loosen this feeble hold, and allow its body to sprawl away at right-angles to the 
food-surface, free in the water, the foot being bent up to the belly.—P.H.G.] 
Length. Total, ;3; inch; of lorica, 4; inch. Habitat. Fresh waters (P.H.G.): 
common everywhere. 
C. RUSTICULA, Gosse, sp. nov. 
(Pl. XXIV. fig. 6.) 
[SP. CH. Lorica regularly ovate, with the frontal opening very narrow ; dorsal 
surface coarsely tessclated ; ventral plate nearly flat ; toes blade-shaped. 
This fine species is very hyaline, notwithstanding that the broadly-oval and arched 
surface is cut into facets. These are not very regular, nor very distinctly marked, haying 
the appearance of folds in leathery skin. They appear to be limited to the carapace. 
This is turned-in along each side, with a sharp lateral angle meeting the edge of the 
ventral plate, similarly turned-in, as is clearly seen when the creature is viewed from 
behind (fig. 6b). The union is doubtless completed by a flexible and extensible membrane. 
The head is included between firm plates, which, seen vertically (fig. 6), appear as 
two lateral projecting points, between which the front, of many conical lobes that carry 
vibratile cilia, works to and fro. The brain and its lozenge-shaped eye are normal; and 
so are the great trophi, the stomach with trigonal gastric glands and distinct intestine, 
and the ovary. A contractile vesicle is sometimes conspicuous, but no details of the 
respiratory nor of the muscular systems have been defined. A rather thick and short 
foot, rounded laterally, bears the two toes, which are articulated with round condyles. 
They are moderately thick blades of fusiform outline, when seen laterally, thinner 
towards the base, and rather bluntly pointed. 
I first met with this form, in July 1885, in the sediment of water in which aquatic 
weeds had been sent from the north of London. Subsequently other examples occurred, 
in water from Caversham and Woolston, and from near Dundee, in December. 
The earlier specimens were even more clumsy and sluggish than ordinary, moving 
waywardly from side to side, as if not quite under control, adhering all the while by the 
toes. Hence I called it rwsticula. This, when too late, I would have changed; for some 
were much more attractive, transparently beautiful, with the eye large and of a lovely 
rose-pink hue, and so sprightly in manners as to be worthy of a more courtly designa- 
tion. In these, too, the digestive canal was distended with food of a clear rich orange- 
brown hue. These were Woolston specimens. Scottish examples bred freely and in- 
creased in my phials.—P.H.G.] 
Length, ;3, inch. Habitat. Pools throughout England and Scotland (P.H.G.): 
common. 
1 In one example the ovary was fastened, by two threads with swollen enlargements, to each side of 
the lorica, near the middle; and the gastric glands were also tied to the same points (fig. 4). Long 
threads (muscular ?) with like enlargements were seen to pass from the foot-bulb to near the same 
points, if not higher. 
