Chapter XI — 173 — Carnivorous Fungi 



in response to the mechanical stimulus provided by the short hypha. 

 At the end of this interval it can now be shown by staining methods 

 that the callus plug has been emptied and that it has swollen and 

 spread out to involve the entire ciliary apparatus, which is now ren- 

 dered useless. In this condition the animal finds its weak foot useless 

 in effecting escape, and in the course of another period of twenty 

 minutes it ceases to struggle. From these observations Gicklhorn 

 draws the following conclusions. In the first stage of capture, there 

 is no adhesive effect on stimulation of the short hypha, as Sommer- 

 STORFF thought, but repeated mechanical grasping of it by the re- 

 tractile ciliary apparatus of the animal. Secondarily there follows 

 the excretion of the mucilage. This is an active process on the part 

 of the hving short hypha on stimulus, and is not a simple swelling 

 of the membrane. He tried, with success, to stimulate short hyphae 

 to throw off their mucilage by stroking them with a fine hair. The 

 short hypha now begins to send out haustoria which penetrate through- 

 out the body of the animal. Even at the end of digestion, the mucilage 

 plug, which can still be seen, is found to have hardened and become 

 yellow in color, holding the shell of the animal in position. The 

 growth of the haustoria proceeds till the interior of the body is a mass 

 of hyphae which send out conidiophores projecting from the animal 

 and in swarm-spores produced in a sac which escape through the 

 mouth end. 



A plant with a similar method of capturing its prey as that em- 

 ployed by Zoophagus insidians is Sommerstorffia spinosa, described by 

 Arnaudow (1923). Both of these species have been collected in 

 Massachusetts and observed by Sparrow (1929). 



An extraordinary group of fungi which prey upon species of Amoeba 

 and shelled rhizopods has been uncovered and studied by Drechsler. 

 His accounts include the minutiae of taxonomic interest as well as 

 the mode of capture. We need not take consideration of the former 

 here. They are nearly all plants with septate hyphae producing 

 conidia of various forms, and in some cases the sexual method of 

 reproduction is known. The method of capture is quite similar in 

 all cases. The species of Amoeba appear to be large. Amoeba ter- 

 ricola or related species being often the victim. There is evidence 

 that certain fungi can attack only one kind of Amoeba and not an- 

 other. In some fungi an adhesive has been observed, in others not, 

 leaving it for conjecture that a non-visible adhesive occurs. There 

 is seldom any preformed structure with the function of capture, but 

 this occurs in Dactylella tylopaga Drechsler. In this "prolate el- 

 hpsoidal protuberances" are provided with an adhesive. An animal 

 sticks to one of these, which then sends out a tube of penetration. 

 This grows inside the animal into a branching mass of short h>^hae 

 which absorb the body of the animal. 



Pedilospora dactylopaga captures shelled Rhizopods (Drechsler 

 1934). Eight species of Acaulopage have been described by Drechs- 

 ler, all of which capture Amoebae in much the same way as Dac- 

 tylella tylopaga except that there is no special organ involved in capture. 

 "An Amoeba after capture is always to be seen attached whether 

 to a mycelial element or as is often the case in some species, to a 



