76 THE EOTIFEEA. 



duals, lamellaris and muticus, which he supposed one and the same ? I confess I have 

 had suspicions that these are but one species. I have had specimens in my live-box of 

 what seemed lamellaris, with the three caudal spines clear enough ; yet in a few 

 minutes I could find only specimens of muticus, with no spines at all to be discerned, to 

 my great bewilderment. It seemed as if the spines could at will disappear, but I cannot 

 conjecture how. This has happened repeatedly. Except the greater development of 

 the neck, there is little else to discriminate the two. P.H.G.] 



Length, T ^ inch. Habitat. Fresh waters around London ; an aquarium at Tor- 

 quay (P.H.G.) : scarce. 



S. UNISETATUS, ColUllS. 



(PI. XXI. fig. 8.) 

 Steplianops uniscta . . . Collins, Science Gossip, 1872, p. 11, figs. 9a, b. 



[SP. CH. Lorica ovate, its hinder end without points, but bearing a dorsal spine, 

 very slender, straight, as long as the body ; foot with a slender tail and two toes. 



The discoverer of this interesting form has furnished me with a number of examples 

 from its original habitat: all inhabiting the leaves of a subaquatic moss. In the " Jour. 

 Roy. Micr. Soc." 1885, Dr. Hudson has suggested the identity of Mr. Lord's species ' with 

 this ; but I think its thick fore-parts, the curvature of its spine, and several other pecu- 

 liarities, indicate their diversity. If so, we have five dorsal-spined species. The spine 

 here is so attenuate that it may well be called a seta. According to my observations, it 

 vibrates with the tremulous motions of the body, but has no proper separate motion. 

 Its base is attached to a shelly knob, level with the bottom of the mastax ; it is quite 

 straight, and its point reaches the tips of the toes. The hind edge of the lorica is 

 truncate and unarmed, as in muticus. There are two slender pointed toes, and a minute 

 spinous tail at right-angles from their base. 



The species affects concealment, but occasionally comes out to swim with a smooth 

 gliding motion in the open interspaces ; often subject to a momentary vibration through- 

 out. P.H.G.] 



Length, 2 ^ ff to T | inch. Habitat. Sandhurst (Collins ; P.H.G.) : not rare. 



S. CHL^NA, Gosse, sp. nov. 

 (PI. XXI. fig. 9.) 



[SP. CH. Lorica cylindric, forming a semicircular occipital shield, without any 

 constriction; toe single. 



Ehrenberg's S. cirratus (not yet recognized with us) appears to lead to this, the sides 

 being straight without any neck. The face is oblique, wider than any other part, beset 

 with irregular fleshy lobes, with a retractile lobe forming a kind of chin. A great sac- 

 like brain carries one minute eye, very difficult to be seen. The lorica, without any 

 diminution in width, ends behind in three points, and resembles a short cloak reaching 

 to the loins. From this descends a thick and long foot, whose penultimate joint carries 

 an acute spine at a right-angle, which is a proper tail ; thence a stout taper pointed 

 toe, along whose middle a line may be dimly seen, suggesting two toes soldered into one. 

 The rectum may be traced to a cloaca between the tail and the toe. Its manners are 

 those of its fellows. In swimming, its movements, already rapid, are accelerated now 

 and then by sudden starts, probably predatory. P.H.G.] 



Length, ^ to T ^<y inch. Habitat. Sandhurst : Woolston (P.H.G.) 2 ; pools : rare. 



1 Micr. News, vol. iv. 1884, p. 146, fig. 24. The figure of this Stephanops has one dorsal spine, and 

 one short spine, or tail, sloping upwards, just above the toes. 



2 There are differences in form and size between the Sandhurst and the Woolston specimens, so 

 considerable that possibly these may be distinct species : the former much larger, more slender, the 

 front not sensibly lobular ; the whole animal yellow-tinged. P.H.G. 



