142 THE ROTATORIA. <§. 131. 



Family: Monotrocha. 



Genera : Ptygura, Ichthydium, Chaetonotus, Oecistes, Conochilus. 



Family: Schizotrocha. 



Genera : Megalotrocha, Tubicolaria, Stephanoceros, Lacinularia, Melicerta, 



Floscularia. 



Family: Polytrocha. 



Genera : Enteroplea, Pleurotrocha, Hydatina, Notommata, Synchaeta, 

 Polyarthra, Diglena, Triarthra, Eospkora, C^jdoglena, Theorus, Masti- 

 gocerca, Euchlanis, Salpina, Stephanops, Squaviella. 



Family : Zygotrocha. 

 Genera : Rotifer, Actinums, Phllodina, Noteus, Anuraea, Brachionus. 



BIBLIOGRAPHY. 

 See the works already cited under Infusoria. 



ADDITIONAL BIBLIOGRAPHY. 



Besides the writings of Brighttvell, Huxley, Leydig, and others, quoted 

 in my notes, see the following : 



O. Sch?nidt. Versuch einer Darstellung der Organisation der Rader- 

 thiere, in Wiegmann's Arch. 1846. 



Frey. Ueber die Bedeckungen der wirbellosen Thiere. Gottingen, 

 1848. 



D'Udekem. Bull, de '1 'Acad. Roy. des Sc. de Belgique, XVIII. 1, 

 1851. 



See also the new edition of Pritchard's Infusoria, given under Book 

 first. — Ed. 



CHAPTER I. 



CUTANEOUS SYSTEM. 



§131. 



Nearly all the Rotatoria are covered with a smooth, hard skin,^' which 

 is thrown into folds by the contractions of the subcutaneous parenchyma ; 

 at the anterior extremity only, it is very delicate, and covered with vibra- 

 tile organs, which also move to and fro with the parenchyma. With many, 



1 With Chaetonotus, and Philodtna aculeata, spines. With Noteua, and Anuraea, there ;iie 

 the structure of the skin is quite ditTerent from species whose faceted skin is roughened by iunumer- 

 thJs ; for its surface bristles witli stiff poiuts aud able granulatioua. 



