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. cit.} says that the creature has a minute, and slightly project- 

 ing foot ; which, as Mr. Gosse has stated above, it certainly 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 hyptopus ; 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 oesophagus, and into the stomach. 1 



Length, -^\-g to ,- ff inch. Habitat. Wherever Volvox is numerous : London, 

 Birmingham, Leamington, Dundee (P.H.G.) ; Clifton (C.T.H.). 



Genus FURCULABIA, Ehrenberg. 



[GEN. CH. Body generally larviform, cylindrical, with a tendency to enlargement 

 in the lumbar region ; usually compressed ; front conical, broad, and deep ; eye single, 

 frontal, sometimes wanting ; incus forcipate, much developed, protrusile ; toes tivo 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 

 FurcularicB 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 numerous. 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 Britain. They 

 are wide-spread, and are not very uncommon, in the sediment of pools and ditches. 

 Two species which Ehrenberg placed in his great genus Kotommata, I prefer to place 

 here. P.H.G.] 



1 Dr. Plate (loc. cit.) has described P.parasita (Nutommata parasifa, Ehr.), male and female, as a 

 new species under the name Hertu-igia volvocicola, on account of its having no toes. Dr. Cohn gave 

 an excellent figure of the male in Sicb. u. Roll. Zcits. 1858, but drew the female with two minute toes. 



