40 THE ROTIFERA. 
surface, is a forked projecting pucker of the hardened skin, so greatly resembling the 
notch in the lorica of a Brachionus, that I thought at first that the structures were 
identical. Ehrenberg (loc. czt.) says that the ereature has a minute, and slightly project- 
ing foot; which, as Mr. Gosse has stated above, it certamly has not: but it is clear, 
from Ehrenberg’s description and figure, that he has mistaken the forked pucker which 
I have just described for a pair of small toes; a mistake easily made when the dorsal 
surface is presented to the line of sight from a certain point of view. The animal’s dor- 
sal outline reminds one of Notops hypiopus ; which Rotiferon is also partially loricated. 
I have often seen one of these little creatures ineffectively nibbling at the gonidia of the 
Volvox which it inhabited ; but once I watched one bite its way into what was, I sup- 
pose, a softer place than usual ; and a moment after I saw a long stream of bright green 
globules course swiftly through the mastax, down the cesophagus, and into the stomach.! 
Length, =}; to ,}, inch. Habitat. Wherever Volvor is numerous: London, 
Birmingham, Leamington, Dundee (P.H.G.); Clifton (C.T.H.). 
Genus FURCULARIA, Ehrenberg. 
(GEN. CH. Body gencrally larviform, cylindrical, with a tendency to enlargement 
in the lumbar region ; wsually compressed ; front conical, broad, and deep ; eye single, 
frontal, sometimes wanting ; incus forcipate, much developed, protrusile; toes two fur- 
cate, usually conspicuous. 
It is not easy to attach to this genus such a definite character as shall be really use- 
ful to the student for identification and diagnosis. Ehrenberg is very vague. He gives 
but two distinctive points,—the frontal eye, and the forked toes. The latter is worth- 
less, as being indistinctive ; and the former is unfortunately not constant, or not always 
available. Eckstein’s character for the genus is really but the character of one species, 
inapplicable to others. Yet it is a good genus (as used by Ehrenberg, not by Dujardin), 
and easily recognized in almost all its members, by one who is personally familiar with 
them. Possessing much resemblance to the species of the extensive genus Proales, the 
Furcularig have an aspect, as well as habits, of their own. Both aspect and habits are 
more easily detected than described. The front, more or less a low cone of wide base, 
in vertical aspect, with a minute but usually conspicuous crimson eye set at the very 
point, with no lateral developments—this is doubtless highly characteristic. So also 
are the toes, in general strongly marked, very active, and often thrown spasmodically 
backward, above the body-plane. There is one feature in their habits which is markedly 
prevalent: the predilection which many of them show for darkling retreats, and the 
tenacity with which they cling to them. No hare flees to cover more eagerly. Examples 
will be given in detail presently. 
The species are vivacious, energetic, restless, eager, predatory. The strongly deve- 
loped rami of the powerful incus, moved by proper muscles, are capable of protrusion 
from the face of the front, with a fierce snapping action, in which, however, they are 
rivalled by other kindred genera, such as Diglena and Distemma in particular. The 
recognized species are not nwnerous. Ehrenberg admitted four. To these I have 
added five others, including the F’. marina of M. Dujardin (if, indeed, mine is identical 
with his); but one of Prof. Ehrenberg’s has not been yet met with in Britam. They 
are wide-spread, and are not yery uncommon, in the sediment of pools and ditches. 
Two species which Ehrenberg placed in his great genus Notommata, I prefer to place 
here.—P.H.G.] 
1 Dr. Plate (loc. cit.) has described P. parasita (Notommata parasita, Ehr.), male and female, as a 
new species under the name Hertwigia volvocicola, on account of its having no toes. Dr. Cohn gave 
an excellent figure of the male in Sieb. w. Kill, Zeits. 1858, but drew the female with two minute toes. 
