NOTOMMATAD.E. 87 



the viscera. 1 Its manners are lively and restless ; rarely swimming, but incessantly 

 boring and pushing through the yellow sediment in which it chooses to dwell ; and that 

 so pertinaciously, that when it comes to the edge of a mass, it will not (or very rarely) 

 go on into the clear, but turns back, and bores its path anew. If it does sail out for an 

 instant, it presently stops short, turns tail, and hurries back to its cover. I have seen 

 the pincer-jaws rapidly protruded almost to their full length. I have seen many speci- 

 mens, in water and sediment from the ditch in Button Park, Birmingham, which Mr. 

 Bolton has so successfully explored. 



The new Eotifera Pleurotrocha mustela lately described and figured by Mr. W. Milne 

 (" Trans. Phil. Soc. Glasgow," 1885), is very like the present species. He has represented 

 the male, which closely resembles the female, but is smaller, and devoid of digestive 

 system. The memoir is of high value. P.H.G.] 



Length. About -j-fy inch. Habitat. A ditch near Birmingham (P.H.G.) ; Glasgow 

 (Mr. Milne). 



P. GIBBA, Ehrenberg. 



(PI. XVIII. fig. 8.) 

 Notommata, gibba .... Ehrenberg, Die Infus. 1838, p. 430, Taf. lii. fig. 4. 



[SP. CH. Body compressed; back much arched, deeply incised above the stout 

 foot ; toes slender, pointed, slightly decurved. 



The fore parts are separated from the trunk by a marked infolding, as well as the 

 foot ; this latter constriction, when viewed sidewise, forms a deep sinus. The first 

 example that I met with was in November 1849, in a pond at Battersea Rise. I 

 afterwards found other specimens. The front is prominent and round ; over it pro- 

 jects a semi-ovate plate apparently slightly bent downward, on each side of which 

 is a fine seta. Perhaps the more natural place of this species would be in the (restricted) 

 genus Notommata, near lacinulata. But the ciliated face is prone. The brain descends 

 bag-like, into the occiput, and bears a wart- shaped red eye on its very end. The taper 

 rectum terminates in a cloaca, in the deep posterior infolding. A minute contractile 

 vesicle is in almost incessant contraction. The foot, with its curved toes, is often 

 thrown forcibly back, in the manner of Eattulus. 



The animal is lively, actively swimming, and contracting strongly as it goes, and 

 throwing the toes backward and forward. P.H.G.] 



Length, ^^ to ^-^ inch. Habitat. Battersea ; Stapleton, Yorkshire ; my domestic 

 aquarium (P.H.G.) : rare. 



P. SORDIDA, Gosse, sp. nov. 

 (PL XVIII. fig. 7.) 



[SP. CH. Body nearly cylindrical ; head broad, truncate ; foot very broad, with a 

 depression through the median line ; toes minute, conical. 



This is a somewhat clumsy, ungraceful, unattractive species. The whole integument 

 is flexible, and thrown into transverse folds, though seemingly stiff. ^The corona is 

 broadly truncate, formed by numerous ill-defined globose masses, on which the cilia are 

 grouped. The whole front is capable of little expansion or change, and the motion 

 consequent, not very swift. The mastax is ample, of the Notommatous pattern ; behind 

 which a brain, moderately developed, carries a red eye, on its side. The eye is often 

 invisible ; then suddenly appears as a minute speck (or, as I once saw, two red specks, 

 apparently in contact), or, often, as a well-defined considerable mass of rich colour. I 



1 Herr Eckstein (Sieb. u. Koll. Zeits. 1883, p. 363, fig. 29) describes and figures a pair of minute 

 dark-red points one on each side of the front, whence a brush of setas springs. These I have not seen 

 but cannot doubt that they are of the nature of antenna-, and that the red speck is imaginary. He 

 describes the proper eye besides, and notices the distinct refracting lens, by which it is embraced. 



