OF THE CILIATA. ASTOMA. 569 



a mouth (Stomatoda). Of the former we have in the general history de- 

 scribed two familes, viz. Opaliniea and Peridinisea ; and we shall first pro- 

 ceed to give a systematic account of their several recognized members, and 

 in so doing recHstribnte certain species and genera other^^se classed by 

 Ehrenberg, — for instance, several Opalince described among the Bursaries. 

 Again, in the systems of Dujardin and Perty, several mouthless genera are 

 enumerated which must find their place in the fii'st division of the Ciliata, as 

 adopted by us. Such are the Leucophryina of Dujardin generally, together 

 with a few Ploesconiens and Ervihens, and the Cobalina of Perty. The 

 Peridiniaea of Ehrenberg, again, include two genera, Choitotyphla and Ghce- 

 toglena, which should rightly find a place among Phytozoa ; but, to avoid 

 disturbing the classification employed, we have retained them in the same 

 family. 



Among the Stomatoda are described, not only the families eniunerated by 

 Ehrenberg (see p. 377), but also those constitiited by Perty, Dujardin, and 

 others, — the place of their introduction being determined by the Ehrenbergian 

 group to which they appear to hold the greatest afiinity. 



We commence the systematic account of the Stomatoda \sith the ill- defined 

 and imperfectly obsen'ed family Cyclidina, and take the other Ehrenbergian 

 families in the order sho^^^l at p. 377. With the Yorticellina the Urceolarina 

 of Dujardin and the Yagiuifera of Perty are conjoined, as well as several 

 genera newly instituted. The Ophiydina embrace additional genera ; and the 

 genus Enclielia, wliilst it is, on the one hand, dej)rived of the xer^' heterogeneous 

 organisms introduced into it by Ehrenberg, viz. Actinoplirys, Acineta, and Tri- 

 chodiscus, and which have ali^eady been treated as subfamilies of Pthizopoda, 

 it has, on the other, appended to it the families Tapinia, Apionidina, and 

 Holophryina of Perty, besides several genera named by this naturalist and 

 by Dujardin. The history of Bursarina, Decteria, and Cinetochilina (Perty), 

 is included in that of the Trachelina ; and that of Paramecina (Duj.) and 

 Aphthonia (Perty) in the account of Kolpodea. The Ox5i;richina embrace 

 the Keronina (Keroniens) of Dujardin ; lastly, the Euplotina comprehend the 

 Ploesconiens and Erviliens of the same writer. 



Division A.— ASTOMA. 

 FAMILY I.— OPALIN^A. (Part I. p. 267.) 

 (XXII. 46, 47 ; XXYI. 28, 29.) 

 Ciliated parasitic Protozoa, consisting of a more or less oval sac, which resem- 

 ble in figure many Bursance, and, although often presenting an anterior fold 

 or fossa, have no mouth. They contain, besides the usual molecular matters, 

 a granular nucleus, and multiply by transverse fission. A globular contractile 

 vesicle is absent in all ; but in 0. Planariarinn and 0. uncinata (of Schultze) 

 an elongated pulsating sac occims, recalling in character the so-called dorsal 

 vessel of various higher animals ; and in others, instead of a contractile vesicle, 

 numerous irregularly -disposed saccular spaces occur. The nucleus is not dis- 

 coverable in 0. Ranarum, whilst in 0. hranchiarum one of unusually large 

 volume is found. Oj^alinoi are probably larvae of various vermes, and not 

 independent organisms. 



Genus OPALINA. — The characters the same as those of the subclass. It 

 ^\ill be seen, in the following specific descriptions, that many of the Oixdince 

 have been described by other systematic writers as members of genera of 

 Stomatoda, such as Bursan'a, Leucoplirys, and Paramecli(m. Stein has de- 

 voted much attention to the Opalincv ; and we accept his determination of the 



