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. Daday, who has made a study of the 



/M\ 



PIG. 600. Rotifer vulgaris, as seen at B, with the wheels drawn in, and 

 at A with the wheels expanded : 6, eye-spots ; c, wheels ; d, antenna ; 

 ", jaws and teeth ; /, alimentary canal ; </, cellular mass inclosing it ; 



7/, longitudinal muscles ; /, /, "tubes of water-vascular 

 young animal ; I, cloaca. 



system ; Jc, 



Rotifera of the Bay of Naples, stated that in 1891, 50 species were 

 known from the Baltic, 13 from the Mediterranean, 8 from 

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

 majority 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 the leaves and stems of water-plants, some- 

 times creeping on Algfe, on which some are parasitic, l sometimes 



1 Compare particularly the interesting observations of Prof. W. Rothert in vol, ix. 

 1896, of the Zooloy. Jahrbilcher (Abth. Systemat.), pp. (>72-71i!. 



