in; . ( 212 ) 



Explanation of the Figures in Plate I, exhibiting the Minute OrgO" 

 nizalion of Seven Species of the Infusoria. 



Fig. 1. Nassula elegans, much magnified ; a, the vent ; b, the 

 mouth and dental cr6\vn ; d, the organ which is supposed to secrete 

 the fecundating liquor ; here are also to be observed many stomachic 

 vesicles, which are rendered opaque l)y the violet matter secreted by 

 the animal. 

 ' Fig. 2. The same at the moment of division, and when it ha^ a 

 "dental apparatus in each of the two individuals. 

 ' ' 'Fig. 3. The dental crown isolated and somewhat contracted. 



Fig. 4. Nassula ornaia ; a, the vent, whence have issued the debris 

 of the small infusores, which have formed its aliment ; 6, the mouth 

 and dental apparatus ; c, the ejaculatory organ ; dj the testicle. -) 



Fig. 5. Chilodon cucullulus, (Syn. Loxodes cucullus), exhibiting the 

 dental apparatus j c, c, the ejaculatqry vesicles ; and the stomachs 

 filled with smaller animalcules. 



Fig. 6. Paramecium aurelia ; b, the mouth ; c, c, ejaculatory ^» 

 ■gans. .7 



Fig. 7. Ophrioglena atra, enlarged ; c, Ct ejaculatory organs, ii 

 Fig. 8. and 9. Nolommata clavulata ; c, c, rotatory cilia ; p, pharynx 

 and jaws ; e, the stomach ; ap. appendices of the stomach ; cl. cloacus ; 

 . V, vent ; ov. ovary ; g, g, nervous ganglions ; i. the eye ; ?n. the mus- 

 cles ; /. the tail. 



Fig. 10. Notommala centrura, Eh. The same letters indicate the 

 same parts as in the foregoing species ; b, b, internal branchial organs ; 

 b, c, brachial canals. ,/ .' 



Explanation of Plate I. 

 Beroe fou7id on the Eastern Coast of Ireland. — Fig. 11. Front 

 view of the lobes of the stomach, and lateral view of the tubes or 

 sheaths of the tentacula. Fig. 12. Lateral view of the lobes of the 

 stomach, and front view of the sheaths of the tentacula. Fig. 13. 

 General appearance and arrangement of the cilia. They are repre- 

 sented somewhat shorter in proportion than they really are, in order 

 to avoid the confused appearance inseparable from the overlapping 

 mentioned in the paper. 



