104 INTRODUCTION TO ZOOLOGY CHAP, vin 



Phylum IX. Rotifera (Wheel animalcules). 



Floscularia, Steplianoceros, Melicerta, Hydatina,Pedalion, 

 Notommata. 



PRACTICAL NOTES ON FLATWORMS, POLYZOA, AND ROTIFERA 



1. Turbellarian Flatworms may be found at all times of the 

 .year gliding over the water-weeds or the stones at the bottom of 



pond or sea. They are useful to keep in a tank with other 

 creatures as they act as scavengers, feeding on dead animal matter. 

 The largest of them is Planaria lactea, which may be an inch long. 

 Leptoplana * is common in shallow sea-water. 



Nemertinesma,jl)Q found in rock-pools between tide-marks, usually 

 hidden under stones; they may be identified by reference to M'Intosh's 

 British Annelids, part i. (published by the Ray Society). 



2. Polyzoa may be looked for on submerged objects in shallow 

 fresh water, or on the under surfaces of floating weeds, where 

 Plumatella, Lophopus, or Cristatella may be found. Any jelly-like 

 mass, not at once recognisable as the egg-mass of some insect or 

 snail, should be removed to a jar of clear water and left undisturbed 

 for a time, when, if it be a Polyzoan colony, the beautiful horse-shoe 

 shaped cluster of tentacles will soon be protruded from the polyps. 

 The common marine forms are stiffer, for instead of the cuticle being 

 gelatinous, as in the fresh-water forms, it is horny or calcareous. 

 Flustra, the Sea-mat, should be searched for on the seashore after 

 stormy weather ; the bladderwrack and other large seaweeds should 

 be examined for the Polyzoans which may form encrustations on 

 them Flustrella and Membranipora are common. 



Any specimens found may be identified by reference to 

 British Marine Polyzoa, by T. Hincks, or British Zoophytes, by 

 A. S. Pennington. 



In all cases the marine specimens should be put into clean sea 

 water and examined first under a lens ; if the polyps are alive a 

 compound microscope should be used, if possible, for the further 

 investigation of their structure. 



3. Rotifers are very common in stagnant fresh water, and a few 

 are marine. Any that are found should be sketched, and identified 

 by reference to The Rotifera, by Hudson and Gosse. 



A full account of the Flatworms, Eound worms, Polyzoa, and 

 Rotifers will be found in the Cambridge Natural History, vol. ii. 



1 Beautiful specimens are obtainable from the Plymouth Biological Station. 



