50 THE EOTIFEBA. 



Length. Of head and body, ^ inch ; of toes, -^ inch ; total length, about j$ inch ; 

 vertical height at hunch, about ^ inch. Habitat. An aquarium (P.H.G.). 



D. FORCIPATA, Ehrenberg. 

 (PI. XIX. fig. 2.) 



Diglena forcipata . - . Ehrenberg, Die In/us. 1838, p. 443, Taf. Iv. fig. 1. 



[SP. CH. Body cylindric, rather stout, obtuse at each end; face long, prone; 

 trophi typically fo rcipate; toes scythe-shaped. 



This is one of the imposing species ; stout, though more larva-like than either of the 

 foregoing. The integument is again firm and thick, and forms tranverse folds, which are 

 constant. The bluntly-tapered head carries the usual decurved fleshy proboscis, whence 

 the ciliated face descends in the ventral plane to a length about one-third that of the 

 body. A turbid brain descends far down the occiput, and bears two minute eyes on the 

 very frontal edge. The mastax and jaws show a fine development of the form normal 

 in this genus, 1 and perhaps they could nowhere be studied with greater advantage. 

 The digestive apparatus differs little from that of D. grandis, or other species, but 

 there is here no projection above the cloaca. The foot is large and bulbous, severed 

 from the body by one of the strong folds ; it bears two toes, which are stout, shaped 

 like the blade of a pocket-knife or scythe. A large contractile vesicle occupies the 

 lower abdomen, which appeared strangely divided into two by a strong constriction. 

 Small vibratile tags were seen on attenuate threads running down each side. 



I made acquaintance with this species, crowding the edges of a jar of water dipped 

 from the " Black Sea " at Wandsworth, in January 1850. It was active, but little given 

 to locomotion. Its numerous cilia are in constant agitation, and appear pale blue 

 by reflected light ; while the minute ruby-like eyes sparkle on the colourless body, the 

 turbid parts of which are like whitish clouds. What I have called the proboscis may 

 possibly be a broad lip, for it is visible only from the side. The wide spread of the 

 toes is characteristic. 2 P.H.Gr.] 



Length, -^ to 7 J 2 - inch. Habitat. Domestic aquaria near London, and Torquay 

 (P.H.G.) ; Sandhurst, Berks (Collins). 



D. CIRCINATOK, Oosse, sp. nov. 

 (PI. XIX. fig. 4.) 



[SP. CH. Body slender at each end, gibbous in the middle; proboscis acute; 

 niastax moderate; toes slender, strongly incurved. 



The fore parts are slender and nearly cylindrical (but flattened on the oral surface), 

 swelling somewhat suddenly to a great ovate body, gibbous on the back, but flat on the 

 belly ; and as suddenly diminishing behind to a rather thick and short foot, which carries 

 a pair of toes, each one a very regular quadrant of a circle in outline, broad at the base, 

 running off to a very fine point. These toes are decurved, and also incurved towards 

 each other, like the legs of a pair of calliper-compasses ; and often thrown widely 

 apart. The skin is very flexible, and, as the animal is every moment lengthening and 

 contracting, and throwing itself into the most varied contortions, makes many irregular 

 folds ; yet the form delineated always recurs, and is evidently characteristic. The 

 under surface has a remarkable projection (fig. 4a), pointing obliquely backward, more 

 or less conspicuous, visible sometimes on each side in the dorsal aspect (fig. 4). This 

 seems the limit of the ciliated face. The very front is furnished with a hook, which is 

 capable of being thrown forward, as if hinged or jointed ; and apparently sidewise also, 

 for it is occasionally glimpsed for an instant, at either side of the head. This process is 

 not a bent finger, but a regularly curved hook, hard and sharp-pointed. After a while 



1 They are described and figured in my Mom. " On the Hand. Org." (Phil. Tr. 1856) 435, figs. 50, 51. 



2 The animal described and figured by Mr. J. E. Lord (Microsc. News, 1884, p. 146, figs. 23a, b, c) 

 is, I l^ave little doubt, the present species. 



