DINOCHARIDA. 73 
This Dinocharis was discovered by Dr. F. Collins in 1866, in a small pool in a wood 
near Sandhurst. Dr. Collins sent it to Mr. Gosse, who figured and described it (oc. czt.) 
in 1867. Dr. Max. Perty’s Polychetus subquadratus may possibly, but not probably, be 
the same creature; if so, it is most inaccurately drawn and described. Mr, Archer's 
Polychetus spinulosus is undoubtedly D. Collinsit. 
Mr. Gosse says of its habits that ‘‘it is rarely still, rooting among the sediment or 
swimming with a smooth gliding motion of no great speed. If I may judge of its be- 
haviour in freedom from what is seen while under our notice, it seems to be a specially 
bottom-frequenting form.” 
Length, ;3, inch. Habitat. Sandhurst, Berks (Dr. F. Collins); Clifton (Mr. 
Brayley) ; Carrig and Callery districts, Ireland (Mr. T. Archer) ; Dundee (P.H.G.): rare. 

Genus SCARIDIUM, Hhrenberg. 
GEN. CH. Lorica vase-shaped and compressed ; or pear-shaped and depressed in 
front ; very thin, transparent, smooth, without spines or projecting plates ; head with 
a chitinous cuticle, except in front; eye single, really or apparently attached to the 
mastax ; foot without spurs ; toes very long. 
In the genus Scaridiwm the foot and toes (especially the latter) are remarkable for 
their great length, for the distinct condyles, which give them such free action, and for 
the powerful striated muscles, which enable the animal to jerk its long toes widely 
apart, and to strike the water violently with its foot, so as to make it an effective organ 
of locomotion. -In both species the lorica is a transparent, thin, stiff skin, which ap- 
pears to be continued over the foot ; but its shape in the two species is very different : 
for, while the lorica of S. longicaudum recalls that of Dinocharis pocillum, the lorica of 
S. eudactylotum somewhat resembles in general outline that of a Brachionus. In each 
species the eye appears to be attached to the mastax, instead of to the nervous ganglion ; 
this would be a very unusual arrangement, but it is possible that the appearance is due 
to the nervous ganglion’s being closely applied to the mastax, and more than usually 
transparent.!. The habits of the two creatures are similar. They swim quietly for a 
time, trailing the foot and toes behind them in an elegant curve; and then, with a 
sudden leap, they dart off into a new course. 
§. Loneicaupum, Ehrenberg. 
(Pl. XXI. fig. 5.) 
Scaridium longicaudum - : = Ehrenberg, Die Infus. 1838, p. 440, Taf. liv. fig. 1. 
” +, . : . . Gosse, Phil. Trans. 1856, pl. xyii. figs. 64, 65. 
[SP. CH. Body compressed ; front truncate ; eye adherent to mastax ; body, foot, 
and toes of about coequal length. 
The most remarkable peculiarity of this species is the anomalous character of the 
eye,—a large flattened capsule, with crimson pigment not quite filling it, permanently 
attached to the surface of the mastax, and apparently not connected, as usual, with the 
occipital brain, which, however, presses upon it from aboye and behind. The trophi, 
too, are very abnormal. (See my Mem., loc. cit.) The animal, with its long unwieldy 
foot and toes, reminds us, not less by its movements than by its form, of Dinocharis. 
It is active, swimming with unequal, not very swift, action, with little movement of the 
foot and toes. It has the habit of making sudden springs, using, apparently, for this 
purpose, the fore parts, not the toes.—P.H.G.] 
‘ I suspect this to be the case in S. eudactylotum ; but in S. longicaudum Mr. Gosse is confident that 
the eye is inseparably seated on the mastax. 
