NOTOMMATAD^E. 61 



the slender fore parts were retracted, and then from the gibbous body was seen project- 

 ing a curious little puckered bundle of transparent flesh and skin, as shown at fig. 4b. 



This species I first found in the sediment of one of my indoor tanks among decaying 

 conferva and milfoil : this was in June 1885. Afterwards it occurred again in a tube 

 sent from Dundee by Mr. Hood. All the features were exactly the same as before ; but 

 this was more impatiently restless. I thought I saw a pair of frontal eyes, but I could 

 not be quite positive. In a brief quiescence I made a careful study of the trophi, whose 

 points are in contact with the very skin of the front. P.H.G.] 



Length, T ^ inch. Habitat, An aquarium at Torquay ; Dundee (P.H.G.). 



D. GIBAFFA, GoSSe, Sp. nOV. 



(PI. XIX. fig. 9.) 



[SP. CH. Body slender, necked; eyes distinct, frontal, protuberant; toes slender, 

 straight. 



This form, having some resemblance to D. circinator, differs from it, not only in the 

 more marked neck, but in the toes being quite straight instead of circularly curved. 

 For, though this may seem an unimportant character, I think the form of the toes will 

 be found to present remarkable constancy in the same species. In circinator I could 

 not be certain of eyes, but in this species they are well-marked, though minute, of dark 

 hue, situate on the very front of the head, so close to the skin as to be prominent as 

 tiny black warts on the surface. The head is small, and its connection with the body 

 is by a sort of neck which can be greatly lengthened and attenuated, as the animal 

 makes its frequent explorations through the free water in all directions, feeling about, 

 very much as an earthworm does in the air. For this the skin is very flexible and 

 versatile. The abdomen is tumid ; but not so abruptly gibbous as in circinator. The 

 foot is taper, and the toes moderately long, straight in every direction, not blade- 

 shaped, but regularly diminished to great slenderness, and very fine points. There is 

 no tail. Beneath the eyes the front forms a well-marked proboscis, which takes the 

 shape of a decurved hook. At times this appears of equal thickness throughout, and 

 blunt, or even truncate ; then it is distinctly seen in the same individual much length- 

 ened, and tapering to a fine point. Can the terminal part be protrusile ? The ciliated 

 face is quite prone, and appears to run far back on the ventral surface, where a chin-like 

 prominence indicates the end of a ciliated furrow. (See Diglena forcipata, fig. 2a.) 

 The skin, though flexible, seems very strong ; it is continually thrown into folds by the 

 unceasing contortions and contractions of the animal ; it looks leathery, but is perfectly 

 colourless and brilliantly transparent. It is a lively, vigorous, attractive creature ; 

 pushing among the sediment, occasionally swimming with a smooth gliding motion. 



I found another specimen in the same water, exactly agreeing with the above. It 

 had the odd habit of forcibly contracting the foot, and throwing back the toes, as far as 

 the tapering outline of the body would allow ; and then protruding the foot with a jerk, 

 bringing the toes at the instant to a right-angle with each other, and therefore horizontal ; 

 immediately repeating the curious action ; and so for fifty times together. When 

 swimming glidingly, it will suddenly quicken its pace an instant, and make a sensible 

 snap, as if it seized something ; and this again and again ; though my eye could detect 

 no atom in the clear water. P.H.G.] 



Length, T ^ inch. Habitat. Woolston (P. E.G.) : rare. 



D. CAUDATA, Ehrcnberg. 



(PI. XIX. fig. 8.) 



Diglena caudata . . . Ehrenberg, Die In/us, p. 4<15, Taf. Iv. fig. 6. 

 [SP. CH. Body cylindric, long, slender ; front broadly truncate, with two frontal 

 colourless eyes; foot short, rcri/ thick, with two long straight slender toes. 



It is excessively versatile and variable in form, constantly contracting into inde- 



E 2 



