296 Characteristics of Rotifers. 



common rotifer in a slime which forms on the cotton thread of a 

 Mason's Hygrometer, where the supply of food must have been 

 exceedingly small. They get into the cells of certain mosses, 

 into the tubes of confervse, and Mr. Gosse described in " Mic. 

 Trans ., 1850/' a form of Noto mm ata ('parasitica), inhabiting the 

 sphere of Volvox globator. 



The rank to be assigned to rotifers, or rather their place in 

 the animal series, has been warmly discussed — most physi- 

 ologists coinciding with von Siebold and Huxley, by whom 

 they are associated with the worms, or rather with that portion 

 which Mr. Huxley designates Annidoida. He says, "the 

 terms of resemblance are these : — (1.) Bands of cilia re- 

 sembling and performing the functions of the wheel organs are 

 found in Annelid, Ikliinoderm, and Trematode larvse. (2.) A 

 water- vascular system essentially similar to that of the rotifers 

 is found in Monoecious Annelids, in Trematodes, in Turbellaria, 

 in Echinoderm, and perhaps in the Nematoidea. (3.) A similar 

 construction of the nervous system is found in Turbellaria. 

 A somewhat similarly armed gizzard is found in the Nemertidai, 

 and the pharyngeal armature of a Nereid larva may well be 

 compared with that of Albertia. (5.) The intestine undergoes 

 corresponding flexures in the Echinoderm larvas. There are, 

 therefore, no points of their organization in which the rotifer 

 differs from the Annuloida." 



It is an interesting question whether any of the rotifers 

 possess true-jointed limbs. Mr. Gosse says of Dinocharis — 

 " This genus is remarkable for possessing true joints in the 

 foot; not merely telescopic inversions of the skin, but per- 

 manent articulations with swollen condyles resembling those 

 of the antennas of a beetle. This fact helps to indicate that 

 this class of animals has its proper affinities with the Articu- 

 lata, which has been denied by most naturalists.'" 



Should, which seems probable, the rotifers retain the place 

 assigned to them by Siebold and Huxley, their relations with 

 other groups as pointed out by Mr. Gosse are nevertheless very 

 likely to be strengthened by further investigation. 



DESCRIPTION OF PLATE. 



1. Side view of Asplanclina Briglitwelli, showing stomach 

 with two egg-shaped glands, the ovary and large resting- 

 egg, magnified 80. 



2. The jaws, magnified 240. 



3. Portion of ovary, magnified 100. 



4. Stomach currents, magnified 1000. 



5. Portion of water-vascular system with tags : the dark 

 lines down the tags represent internal ciliary action, magnified 

 about 1000. 



