Tardigrada.} inftjsoeiai animalcules. G85 



The Tardigrnda on the one side stand between the "Rotatoria 

 (Sj'Stolides Duj.) and the HeLninthides ; and on the other, the 

 Annelida and Arachnida. 



These creatiu'es are usually found attached to aquatic plants, which 

 float upon still water. I first obtained them from ponds in the 

 Regent's Park. By placing some water with the plants in a common 

 white hand-basin, and shaking the vegetation, they are detached, and 

 fall to the bottom of the basin, from whence they are readily taken 

 They are generally met with, in company with the larger kinds of 

 Rotatoria, in moss. They are very sluggish in their movements, and 

 arc commonly known imdcrthe name of "little water bears." Under 

 the polcU'iziug microscope, the manducatory apparatus exhibits the 

 same appearance as horn. They are capable of resuscitation after 

 being dried. They vary in length from the 1 -20th to 1 -50th of an inch. 



M. Doyere, in an elaborate Memoir in the Annales des Sciences, 

 has divided the Tardigrada into foiir genera : — 



Genus Emtditjm. — Body oval, anterior part narrow, and ter- 

 minating in a pointed mouth, near to which, on each side, are flesh- 

 like papillae. Feet anned with four distinct claws ; colour reddish. 

 Found among moss (Bryum). Figures 1 and 2. 



Genus Maceobiotijs. — Body more cylindrical ; obtuse anteriorly j 

 no setae ; each foot furnished with two claws. I'ound with the pre- 

 ceding ; also in rivulets (see figure 6.) 



Genus Taedigeada. — Body stout, oblong ; mouth not so sharply 

 pointed. Foimd in stagnant water, on aquatic plants, and on the 

 Hypnum fluitans. (See figures 3, 4, and 5.) 



Genus Mixnesium. — Characters unknown. 



For further pai'ticulars consult Ann. des Sciences, t. 14, p. 269, 



