786 



MICROSCOPIC FORMS OF ANIMAL LIFE 



SECTION II. ROTIFERA, OR WHEEL-ANIMALCULES. 



We now come to that higher group of animalcules which, in 

 point of complexity of organisation, is as far removed from the pre- 

 ceding as mosses are from the simplest protophytes, the only point 

 of real resemblance between the two groups, in fact, being the 

 minuteness of size which is common to both. A few species of the 

 wheel-animalcules are marine, or the inhabitants of brackish pools 

 near the seashore. Dr. E. v. Daclay, who lias made a study of the 



I > 



II 



FIG. 600. lititifn vulffaris,as seeiiat H. with bhe wheels drawn in, and 

 nt A with the wheels expanded: It, eye-spots; /-, wheels; il, antenna; 

 c, jaws and teeth ; /, alimentary canal ; .'/, cellular mass inclosing it ; 

 //, longitudinal muscles; /, /, tulies of water-vascular system; /,-, 

 young' animal ; /, cloaca. 



I lot item of the Bay of Xaplcs. stated that in 1H1M. ")() species were 

 known from tlie Baltic, 13 from the Mediterranean. H from 

 elsewhere, hut 32 of these occur also in fresh water. The vast 

 majorily known to us belong, therefore, to fresh water, and are to be 

 found in ditches, ponds, reservoirs, lakes, and slowly running streams 



sometimes attached to tile leaves and steins of water-plants, some- 

 limes creeping on Alga-, on which some are parasitic. l somet hues 



1 Compare particularly (lie interesting O!>MT\ at ions ol' 1'rof. W. Rothert in vol.ix. 

 1890, of the Zoolog. Itihi-li'i'n-hrr (Aljth. Svstemut.), \i\\ (<~-2-li->. 



