Chapter XI — 171 — Carnivorous 



much knowledge about these to Drechsler, who points out (1933c) 

 that some species have loops the component cells of which do not 

 swell to constrict the loop, and that these catch their prey by means 

 of a strong adhesive found on the inner surface of the loop. It is 

 not unlikely that this is the case in the plant studied by Zopf who 

 did not observe constriction of the loops. One species has the loop 

 borne on a very slender stalk which may be broken off during the 

 struggles of the worm, but this does not obviate death and destruc- 

 tion, as the cells of the loop can still form their penetrating hyphae 

 (Drechsler, 1933^). 



Some of these species, e.g. Dactylaria Candida (Nees) Sacc, have 

 in addition to the loops a second organ for the catching of the prey, 

 called "globular" bodies. These are round knobs on short hyphae. 

 On the knob is secreted a patch of strong adhesive, by which the 

 eelworm is caught. In the course of a short time, a penetrating haus- 

 torium grows through the adhesive pad and enters the animal's body. 

 In these and the other cases above mentioned, after the prey is per- 

 meated with haustorial hyphae, and after these have withdrawn all the 

 available nutriment, the fungal protoplasm withdraws, leaving an 

 empty shell (Drechsler, 19336, c; 1935c). 



A similar method of capture is used by a species in which the 

 catching organs consist merely of the ends of hyphal branches, pro- 

 vided, as on the globose organ, with an adhesive. The penetrating 

 haustorial tube swells up after entrance, and from the sweUing the 

 haustorial complex of hyphae grows. 



A similar, very striking case of a fungus which catches armoured 

 Rotatoria, the first of its kind known, was described in 191 1, follow- 

 ing Zopf's original discovery of a carnivorous fungus in Arthrobotrys, 

 by SoMMERSTORPF Under the name Zoophagus insidians n. gen., n. sp. 

 This plant grows epiphytically on Cladophora, and consists of a net- 

 work of septate hyphae which bear "short" branches scattered at 

 irregular intervals along them. These short branches have dense 

 glistening contents, and are the organs of capture. Rotatoria (of 

 the genera Salpina, Metopidia, Colurus, Monostyla), feeding among 

 the threads of the algae and associated fungus, take hold of the ends 

 of the short branches, and remain attached, unable to break loose. 

 By pulHng ofT a newly captured animal he (Sommerstorff) was able 

 to determine that the end of the hypha had enlarged, apparently by 

 the swelling of the membrane, which now took up methylene blue 

 with avidity. Previous to having captured an animal, there appears 

 to be no adhesive, since no detritus could be observed sticking to 

 the ends of the short branches, nor did they take up the stain. Som- 

 merstorff concluded that the swelling takes place on the stimulation 

 occurring when the animal takes the short branch into its mouth. 

 Generally the prey cannot escape, despite his size. But as it has 

 no other organs of locomotion save the cilia, the 'tail' only is avail- 

 able for struggling. If he can get leverage with this on a neighboring 

 algal filament, he may and sometimes does escape. After struggling 

 ceases and death is intervening, the capturing branch grows into a 

 penetrating tube which then sends numerous thin-walled haustorial 

 hyphae to withdraw nutriment. 



