ADVANCE IN LOWER PLANT AND ANIMAL FORMS 



PLATE LXXIII 



^IS 



PLATE; LXXIII 



This plate illustrates the presence of cilia in large numbers in Infusoria. They occur on various parts of 

 the body and have a high significance functionally, as they act as organs of locomotion, produce currents which 

 assist in ahmentation, and, in some instances, entangle food. Several of the figures reveal longitudinal and trans- 

 verse markings (incipient and real segmentation) ; others indicate spiral structure. 



Fig. 1. — Encysted animalcule {Ceralium divergens), x 500. 



Fig. 2. — Similar animalcule with carapace cast oft'. 



Figs. 3 and 4. — Animalciili- (Cfymnodiniuin lachmanni) dividing by longitudinal iission, x 300. 



Figs. 5 and 6. — Two monads {Gymnodinium marlnum), one of which (Fig. 6) is devouring a smaller monad, x 600. 



Fig. 7. — Anoplophrya filum covered with cilia and displaying numerous contractile vesicles (<■?'), x 120. Shows transverse 

 division of segmentation. 



Fig. 8. — Adult animalcule (Anoplophrya prolifeni), ciliated ; affords a good example of transverse division or segmentation, x 120 

 (Clap, and Lach.). 



Fig. 9. — Adult zooid [Hoplitophrya lumbrici), ciliated; dividing by transverse fission, ri; cv, Contractile vesicles; u, m, horny 

 uncini ; n, nucleus, x 200 (Stein). Shows trace of internal skeleton. 



Fig. 10. — Paramecium aurelia, ciliated ; remarkable for its powers of progression, n, Nucleus ; cv, cv, contractile vesicles, x 200 

 (Miiller). 



Fig. 11. — Two ciliated zooids conjugating and fusing. 



Fig. 12. — Adult animalcule {Opalina ranarum), ciliated ; showing striation, x 100. 



Figs. 13, 14, 15, 16, 17, and 18. — Show successive phases of division ending in the production of minute ovate zooids with one, 

 two, or more nuclei. At Figs. 15 and 18 are seen phases of zooid re-emerging from the encysted state; the zooid at Fig. 15 having 

 only one nucleus, that at Fig. 18 having three nuclei, the lower one of which («) is in tlie act of subdividing. At Fig. 17 a young 

 zooid with ragged pseudopodium-like lateral extensions is represented (Ernst Zeller and Engelmann). 



Fig. 19.— Adult ciliated zooid {Anoplophrya filum), x 200. n, Nucleus; cv, cv, contractile vesicles (Ray Lankester). 



