AN OLIGOCH^TE WORM. 303 



steadily decreased until, in about a month's time, I could not find 

 a single mature worm. This heap of leaf-mould, which was 

 situated in a gai-den in Edgbaston, Birmingham, has been my 

 chief source of material. In the same heap were also numbers of 

 the " Gilt-tail," Dendrohmna suhruhicunda ; this is interesting, as 

 Friend has also noticed that certain Enchytrfeids are often 

 associated with certain of the larger earthworms. A favourite 

 retreat of the Enchytrseids was between 2 or 3 decaying beech- 

 leaves that had been tightly compressed, a handful of such decaying 

 leaves often yielding 40 or 50 worms, many of which were quite 

 mature. But I have also found groups of these worms between 

 sheets of damp compressed paper in the heap, although one 

 would be surprised if they obtained much nourishment from 

 that. They w^ere also faii'ly abundant on the under side of stones. 

 They wei-e very rarely present in any loose material, but seemed 

 to prefer compressed material. Occasionally I have seen these 

 Enchytraeids boring their way inside blackened decayiug leaves 

 between the upper and lower epidermis. They were feeding on 

 the soft tissue of the leaf, as an examination of the contents of 

 the gut showed, and this suggests that Enchytrteids may be quite 

 an important factor in the formation of leaf-mould. Tiiese 

 Enchytrjeids are also very gregarious in their habits ; one often 

 wonders if this is due to the worms collecting together at some 

 point where there is a special advantage, e. g. nourishment, or 

 whether it is due in some manner to rapid multiplication, owing 

 perhaps to a similar advantage. I have isolated numbers of 

 specimens with a view to seeing whether Enchytrseids are capable 

 of fission, but so far with a negative result. 



Anatomy. 



The Pharynx, which is just behind the buccal cavity and 

 occupies segment 2, is interesting because of a large pharyngeal 

 ingrowth. This is an ingrowth of cells from the dorsal side of 

 the wall of the pharynx. It occupies segments 2 and 3, and is 

 composed of elongated spindle-shaped cells, which run doi-so- 

 ventrally. The nuclei of these cells are large, elongated, and 

 distinct (PI. XLVI. fig. 4), This pharyngeal ingrowth almost 

 obliterates the cavity of the gut, i-educing it to a small ventral 

 channel. There is some connection between this ingrowth and 

 the septal glands, but this will be referred to later. In this 

 Enchytrseid there is nothing in the nature of a stylet attached 

 to the pharyngeal ingrowth, which has been described in Enchy- 

 trcBus huchholzii Vejd. (16). This stylet was said to be used for 

 clinging to the roots of plants. The function of the pharyngeal 

 ingrowth is not quite plain, but it may be some kind of sensitive 

 organ, as these Enchytrseids, when irritated, often evex't the whole 

 of the pharynx spasmodically, the pharyngeal ingrowth then 

 hanging out like a tongue. The pharynx is extremely muscular, 

 the muscles running obliquely backwards from it to the body- 



