186 



THE THEORY OF EVOLUTION 



Copepods (Swimming Crabs). Fig. 34 shows some 

 of the most striking transformations. In the plant 

 kingdom parasitism is also widely extended. Exclusive 



parasites especially 

 are many fungi and 

 bacteria ; they are 

 often dependent 

 upon ( quite definite 

 animals and plants 

 and even upon nar- 

 rowly limited parts 

 of them/ 1 Often, 

 however, they can 

 find their nourish- 

 ment in dead 

 organic remains (sa- 

 prophytes). 



With the Parasites 

 in the series of 

 higher plants we see, 

 precisely as with 

 animals, a feeble 

 formation or a per- 

 fect absence of those 

 organs which serve 

 for independent nutrition namely, the leaves and roots. 

 The non-chlorophyllic leaves of the Dodder (Cuscuta 

 Irifolii} are small yellowish scales. With many tropical 

 parasites the body of the plant is reduced to the flower, 



1 Strasburger : Lehrbuch, p. 195. 



FIG. 34. COPEPODA. 



1. Free-living Canthocamptus minutus 

 (after Glaus) : la, seen from the side ; Ib, 

 nauplius stage. The following are parasitic ; 



2, Carplouse Argulus foliaceus (after Glaus) ; 



3, Achtheres percarum, female (after Glaus) ; 



4, Chondr acanthus gibbosus (after Glaus) ; 

 Lerncsonema monillaris ; 6. Lernceocera cyp- 

 rinacea (after Nordmann) ; 7, Peroderma 

 cylindricum, (after Riclitardi). Explanation 

 of letters: an, antennae; c, tail; ct, main 

 thorax; k, jaw; kf, jaw foot; o, egg sac (in 

 4 and 5, only partly shown) ; s, sucker ; t, 

 breast segments ; w, suction roots. The 

 figures show, from left to right, the 

 graduated transformation of the Copepoda 

 type into shapeless bodies. The females 

 show only still the characteristic two egg 

 sacs of the Copepoda. (After von Graff.) 



