PrcdQc .fungi j2 



the like, \inless they are partly dried. Any eelworm that comes in con- 

 tact with such a network is held fast. One can easily see ixnder the 

 microscope that there is a secretion of quite a large quantity of 

 sticky fulid. It is extremely efficient; if anyone could manage to 

 isolate it, to synthesize it, and to market quantities of it as a glue, 

 he would make a fortune. I have never known of an eelworm getting away 

 once it is fairly held. 



After the worm has been capturedin the network, there is then a small 

 outgrowth from the fungus which penetrates the eelworm. The outgrowth 

 developes into a large bulbous structure; and from this infection bulb, 

 hyphae grow inside the body of the eelworm, absorbing its contents. 

 Within about 2k hours there is nothing left but the empty cuticle of 

 the eelworm filled with the hyphae which absorb the body contents of 

 the nematode. Incidentally, the worm apparently dies m from one to 

 two hours after capture. Death takes place before the intrusion of the 

 bulbous structure. What exently kills the eelworm, we do not yet know. 

 The only thing I can think of is that it dies of fright. 



A rather simpler form of sticky trap is the adhesive process, or ad- 

 hesive branch, type of nematode trapping fungi. The very common Dacty- 

 lella cionopaga , for example, has branches of one, two, or three cells 

 which go out from its hyphae. These natural branches are sticky and 

 function in the same way as the networks. 



fVom this sticky process type of structure, it is not a very long dis- 

 tance to the adliesive knob type of traps. These have hyphae with 

 short erectile branches on which there are small knobs. One of these 

 knobs usually measures rather less than 10 microns in diameter. Again, 

 these knobs are sticky and are usually orientated on the hyphae. If 

 the fungus is growing on a surface, such as an agar plate, the knobs 

 stand up vertically from the surface. Thus, they are in a good posi- 

 tion for capturing eelworms. 



These knobs are very nvimerous, and they are rather regularly placed 

 apart at considerably less than the eelworm 's length. A worm caught 

 upon one knob, in the course of its struggling, will usually manage to 

 stick its tail on to another knob, and thus be held doubly. These 

 adhesive knobs' are rather less efficient than the networks and branches, 

 in that they do not seem to be able, in most cases, to deal with very 

 large eelworms. The normal limit of the knobs is an eelworm, I should 

 say, 500 microns in length, although larger ones are occasionally 

 captured. I have seen fungi with sticky netx\rorks holding eelworms more 

 than one millimeter long. All these traps depend upon the same princi- 

 ple, the secretion of a sticky fluid. 



We come now to the mechanical type trap, of which there are two kinds. 

 The simplest is the non- constricting ring, which consists of a ring of 

 three cells. The hypha bears a branch which elongates and curls aroimd, 

 joining to form a ring composod of three cells. If an eelworm pushes 

 its head into a ring of that sort and tries to pass through it, it gets 



