72 THE EOTIFERA. 



passes, and its foot either tlirowni into one long curve or oddly bent zigzag fashion, it 

 grubs among the sediment of the live-box ; and sometimes it ghdes gently away by the 

 action of the coronal wreath, with its long toes trailing gracefully behmd it, just like 

 Scaridium cudactylotum. 



Length, ^'^ inch. Habitat. Clear ponds and ditches, Hampstead Heath ; Kew 

 Gardens ; Woolstou (P.H.G.) ; Clifton, Birmingham (C.T.H.) : not very common. 



D. TETKACTis, Ehreiiherg. 

 (PI. XXI. fig. 2.) 

 Dinocliaris ietractis . . . Ehrenberg, Die Infus. 1838, p. 473, Taf. lis. fig. 2. 



SP. CH. Lorica vase-shaped, narroiving to the hind extremity, facetted, without 

 spines ; foot and toes very long, together more than twice the length of the trunk ; spurs 

 ciuxed ; no spine between the toes. 



This species is extremely like D. pocillum, differing fi-om it chiefly in having no spine 

 between tlie toes on the last jomt of the foot. The trunk viewed dorsally has a some- 

 what triangular outline, the apex of the triangle being towards the foot, and is shorter 

 in proportion to the foot and toes than it is in the former species. Mr. Gosse has ob- 

 served m this species that the lorica runs off at the hmd end into three, thm, transparent, 

 and radiatmg plates, of which one is dorsal ; and that this latter is not continued so far 

 forward as the lateral plates, so that a transverse section shows no trace of the dorsal 

 radiating one, but rather a slight depression between two gibbous swellings. This is 

 well showTi in fig. Ic, a transverse section through D. jMcillum. Mr. Gosse has also 

 seen many specimens of D. tetractis, in which the spurs on the penultimate joint were 

 more or less deteriorated ; so that in some they were reduced to short tubercles, or even 

 effaced altogether. These latter specunens were precisely Ehrenberg's D. pauper, which 

 can no longer, therefore, be entitled to rank as a species. 



Length. Up to ^'5 inch (P.H.G.). Habitat Clear ponds and ditches throughout 

 England and Scotland (P.H.G. ; C.T.H.) : common. 



D. coLLiNsii, Gosse. 

 (PI. XXI. fig. 3.) 



Pohjchcclits siibquadratiis {"!) . . . Vevty, Z. Kenntn.kl.Lcb.lSo^. \x iS.Ta.t.X.&s.Ga. 



Dinocliaris CoUinsii Gosse, Ludl. Observer, vol. x. ISCifi, p. 2(;9. 



Polycluetiis spiniilosus .... Ai-cher, Quart. J. Micr. Sci. vol. viii. 1868, p. 72. 



SP. CH. Lorica depressed, siib-quadrangnlar, with serrated edges and eight dorsal 

 spines ; spurs straight ; foot and toes short, together as long as the trunk. 



Though this Rotiferon is clearly a Dinocharis, it is a very singular one. The foot is 

 short, the toes small, the lorica depressed, and a chitinous dorsal hood protects the head. 

 The lorica is somewhat rectangular in shape, but broader in front than behind, with its 

 fore corners rounded off, and its lateral edges serrated. At each hind corner a sharp 

 spine projects, while six others rise from the dorsal surface. There is an outer pair 

 attached to the shoulders, pointing down the back ; and an iimer pair, slightly decurved 

 at the tips, rising from the central highest point of the lorica, and pointing diagonally 

 outwards and upwards. A third pair, sharp and straight, rises fi-om the hind end of the 

 lorica, one on each side of the foot, and pointing outwards and upwards ; while the first 

 joint of the foot itself carries a pair of sharp chitinous spurs. The lorica is closed, much 

 arched dorsally, highest in fi-ont, and flat on the ventral surface. The dense lorica, 

 which is stippled in the central region, makes it difficult to define the internal structure; 

 but Mr. Gosse, fi-om whose Memoir iloc. cit.) this account is taken, succeeded in ob- 

 Bervmg a globose mastax, ample alimentary canal, and rich ruby eye. 



