178 



DESIGN IN NATURE 



PLATE LXXV 



PLATE LXXV 



This plate reveals an obvious advance in infusorial structure and function. It displays suctorial and pre- 

 liensile tentacula ; some of the latter exhibiting beautiful spiral formations and spiral movements ; it also 

 displays modes of division, modes of feeding and differentiation generally. In studying the lower animal 

 forms depicted in Plates Ixvi. to Ixxiii. inclusive it is impossible to come to the conclusion that the one is evolved 

 out of the other. Each in its own way is independent, and the most that can be done is to refer the individual 

 to a type or group having structural, functional, and developmental peculiarities. In other words, no gradual 

 transitions, such as evolution takes for granted, can be made out. 



Figs. 1 and 2. — Extended and spirally coaitracted e.xamples of ciliated zooids (UroUptus 'iiiohilis), x 150 (Engelinaiin). Body 

 flexible, elongate, linear, cylindrical ; peristome very narrow ; frontal styles uncinate ; ventral and lateral setse — the latter lono- and 

 fine ; nuclei or endoplasts six in number and rod-like in shape. " 



Figs. .3 and 4. — Dorsal and lateral views of EpicUnten radiosa, x 300 (Quennerstedt). Body elongate, anterior portion compn'ssed 

 and bearing at its summit five large straight radiating frontal styles ; single marginal row of setse on anterior and middle portions of 

 body and double row bordering caudal portion of body. 



Fig. 5. — Ventral aspect of Uroleptus rattuhis, x 150. n, «, Nuclei (Stein). Body persistent in shape, linear-fusiform anterior end 

 rounded, tapers from central part of body and ends in long thin tail ; peristome iield narrow and extends backward one-fifth of bodv ■ 

 marginal setse cover body, the ventral setie forming two rows ; endoplasts (n, n) two in number with contractile vesicle between' 

 Shape of body fi.sh-like. 



Pig. 6. — Lateral view of Euplotes patella, x 200 (Dujardin). 



Fig. 7. — Ventral view of Euplotes charon, x 300. 



Fig. 8. — The same dividing by transverse fission, x 300, 



Fig. 9. — The same encysted, x 300 (Stein). Figs. 7, 8, and 9 show simple forms of division and development. 



