NOTOMMATAD^E. 89 



thin and blade-like, straight but slightly incurved at the free end, deeply truncate above 

 where the rami are jointed, which are long triangular blades arching backwards. The 

 mallei are slender rods, each with a process, and an uncus of two fingers. 1 



Ehrenberg describes the species as parasitic on the branching Bell-vorticels Epistylis 

 and Carchesium, among whose twigs it lays its eggs ; and also in Volvox. I have seen 

 it always free, though repeatedly in close association with both these Infusoria. I have 

 been acquainted with it from many localities since 1850. It is lively in its motions ; 

 yet frequently adhering to the glass, and moving by a feeble crawling ; it can, however, 

 swim rapidly. Its contractions are almost perpetual, and very vigorous. P.H.G.] 



Length, when extended, T | 7 inch. Habitat. Around London ; Walthamstow ; 

 Leamington Canal ; Cheltenham ; Woolston ; Birmingham : pools and garden reser- 

 voirs (P.H.G.). 



P. PAKASITA, Ehrenberg. 

 (PL XVIII. fig. 11.) 



Notommata parasita . . . Ehrenberg, Die Infus. 1838, p. 426, Taf. 1. fig. 1. 

 Hertivigia volvocicola . . . Plate, Jenaisch. Zeits.f. Natur. 1885, p. 26, figs. 7, 8. 



[SP. CH. Body cylindric or gibbous, rounded at each end ; foot and toes wanting. 

 Parasitic in Volvox. 



To the characters just given may be added that the jaws are long, slender, protrusile, 

 and asymmetric : the mallei being dissimilar in length and curvature ; thus recalling 

 the Battulidce. A brilliant crimson eye, wart-shaped, sits on the dorsal corner of a 

 large occipital brain ; from the front of which projects a club-shaped antenna, some- 

 times drooping, sometimes erect. The prominent round head is clothed with fine 

 cilia, and surrounded by a wreath of stronger vibration ; when this is retracted the 

 margin is thrown into puckers. 



The habits of this inconspicuous species are curious ; for it is parasitic within the 

 spheres of Volvox globator. Examining this elegant creature, we may, even with a 

 pocket-lens, discern which are tenanted, by a spot differing from the young clusters in 

 form and colour. Such a spot proves to be the Proales, snugly ensconced within the 

 globe, in whose spacious area it lives at ease, and swims to and fro like a goldfish in a 

 glass vase. For the most part it affects the inner surface, engaged in devouring the 

 green Monads that stud the gelatinous expanse, or else eating away the embryo clusters. 

 Sometimes laid eggs are present, with the Proales ; sometimes eggs alone. The young 

 seems always hatched in a Volvox, and, entering an embryo cluster, is expelled with it. 

 Often they eat their way out, and swim at freedom. Observing in a globe one large egg, 

 I opened the globe with a needle, and freed the Proales, placing it in water, and adding 

 several Volvoces, all untenanted. But it did not enter one, during several hours' obser- 

 vation. During this period it discharged, loose in the water, an ephippial egg, covered 

 with prickles. I have seen a prickly egg and a smooth one, transparent, with eye and 

 jaws visible, in the same sphere. One of the latter I saw hatched, the young just like 

 the adult. The Volvox appears to suffer little from the depredations of its ungrateful 

 guest. The Proales is lively and energetic in freedom. It glides wildly about, often 

 in a zigzag course, turning from side to side, as it dashes rapidly along. Sometimes it 

 rotates on its axis as it goes ; or, becoming stationary, it turns on its blunt extremity, as 

 on a pivot. It is perpetually contracting and elongating, and throwing itself into angular 

 folds and contortions. P.H.G.] 



This is one of the partially loricated Eotifera. The soft front of the head, seen dor- 

 sally, is truncate, and much like that of Notops hyptopus. The edge of the trunk, within 

 which the head can be withdrawn, is chitinous, and scolloped in regular curves, just like 

 the edge of a lorica. At the hind end of the trunk, and on the median line of the dorsal 



1 Sec Phil. Trans. 1855, p. 4H2, pi. xvii. figs. 27-31. 



