ROTIFERA. 49 



appear in some Rotifers to be in connection with the longitudinal 

 canals : in Lacinularia these ternunate here in a small convoluted knot. 

 Rapidly vibrating or undulating ciliated tags are attached to dif- 

 ferent parts of the vasiform bands. The number of the vibratory 

 tags varies not only in different species, but even in individuals of the 

 same species. In general there are from two to three on each side, 

 sometimes from five to eight, as in Notommata copeus and JV. syrinx ; 

 and in the rare instance of Notommata claviculata as many as from 

 thirty-six to forty-eight have been seen on each lateral band. 



At the anal end of the abdomen the two lateral bands converge, 

 and their longitudinal canals anastomose and open into a common 

 contractile bladder, which expels its watery contents into the cloacal 

 outlet. An aperture, sometimes supported on a special process at the 

 fore-part of the trunk, probably admits the water into the abdomen, 

 where it may be received into the freely suspended lateral canals, 

 and expelled by the contractile bladder. This apparatus is viewed by 

 Siebold with much probability, as subserving respiration. Enteropha, 

 Hydatina, and Diglena, have a simple anterior branchial aperture. 

 Rotifer, Philodina, Brachionus, and some species of Notommata, 

 have a branchial tube : Tubicolaria and Melicerta have a double 

 branchial tube. 



Groups and rows of minute granules may be observed in rapid 

 molecular motion, immediately beneath the integument ; and these 

 are sometimes hurried along in currents, indicative of a circulatory 

 movement. 



The gelatinous cell or tube protecting the body in some Rotifera 

 must be cited as one of the secretions in that class : the gland is 

 situated at the base of the tail in Lacinularia, and its duct traverses 

 that extensile part to terminate at its extremity. Many individuals 

 of Conochilus and Lacinularia may be found in a conglomerate of 

 such gelatinous shells, diverging from their fundus as from a centre. 

 The individuals of Tubicularia, Floscularia, and Stephanoceros are 

 protected in more elongated tube-shaped cells, which are commonly 

 insulated. In Melicerta the protective tube is composed of multan- 

 gular brown corpuscles, expelled from the cloacal opening, and com- 

 pacted together.* 



The Rotifera are of distinct sex ; the females being larger than 

 the males, and almost exclusively the subjects of scrutiny by the 

 eminent micrographers to whom we are indebted for a knowledge of 

 the anatomy of the class. Any other than female organs in these 

 larger individuals has been ascribed to them only on the supposition 



* XXIV. p. 183. 



