86 THE ROTIFERA. 
Genus PROALES, Gosse. 
GEN. CH. Of moderate or small size; body generally cylindric, or larviform ; 
ciliated face more or less prone ; brain clear ; auricles and tail wanting. 
This again is an extensive group, containing many species, some of them of familiar 
occurrence, often obscure, of indefinite character, and hard to be distinguished. Some 
are entozoically parasitic on other creatures. The vibratile cilia are disposed on a face, 
along that side of the head which is more or less in the ventral plane. Their bodies are 
usually lithe, soft, and versatile; their motions rapid and various. 
P. pectrrens, Ehrenberg. 
(Pl. XVIII. fig. 6.) 
Notommata decipiens . : : Ehrenberg, Die Infus. 1838, p. 431, Taf. lii. fig. 6. 
55 vermicularis 5 6 Dujardin, Hist. Nat. Zooph. p. 648, pl. xxi. fig. 7. 
(SP. CH. Body cylindric, slender, worm-like ; foot undeveloped ; toes minute. 
This much resembles a dipterous larva; haying a soft, flexuose, slender body, with 
a rounded front, and two minute, conical toes, without any sensible foot. A large, oc- 
cipital brain carries a red eye, distinct, though small; a crystalline lens is conspicuous, 
seated on, and partly imbedded in, the pigment-globule ; the latter much the larger. 
(See Duj. loc. cit.) Near the front are two clear colourless granules, usually distinct in 
the many examples that I have met with. These may be readily mistaken for eyes 
when the animal is in motion. A mastax with trophi of normal form leads by a very 
long and slender esophagus to a cylindric alimentary canal, with usual accompaniments. 
I first found this in 1849, in waters near London both north and south. Since then 
it has occurred repeatedly in various localities. When I saw my first example, it was 
spinning round on its long axis. After a while it became less impatient, but still very 
lively. It frequently bent itself up double, in the manner of a caterpillar, and occasion- 
ally shrank up into a wrinkled, shapeless ball, remaining thus awhile quiet. Gliding 
through the water by means of its rotatory cilia, its motion was not particularly rapid. 
Though I have called the trophi normal, there is, in the form of the rami, a manifest 
approach to these organs in Diglena.—P.H.G.] 
Length, ;3,; toy}; inch. Habitat. Near London; Epping Forest ; Birmingham ; : 
Stapleton Park, Yorkshire; Dundee (P.H.G.): pools: not common. 
P. rexis, Ehrenberg. 
(Pl. XVIII. fig. 17.) 
Notonunata felis . c 0 . Ehrenberg, Die Infus. p. 431, Taf. lil. fig. 7. 
[SP. CH. Body cylindric, slender ; a large decurved fleshy proboscis ; eye very 
large ; trophi Diglenoid ; foot stowt ; toes slender, pointed. 
Of this little species, the slender trunk is strongly fluted longitudinally. The curious 
projection which Ehrenberg calls a horn, is a thick soft lobe of translucent flesh, which 
curves down before the head, perhaps a tentative organ, and recals what we see in some 
of the Diglene. So also do the pincer-shaped rami; and, as in that genus, they are 
capable of being rapidly and forcibly thrust forth, with a snapping action. The brain is 
broad, and descends far ; it bears on its round extremity an eye so large that it occupies 
fully half the diameter of the body. Yet it is seldom seen; being a lens seated 
transversely, and edgewise to the observer. The stomach too, with high lateral 
shoulders, usually densely filled, hinders the observation, not only of the eye, but of all 
