302 MR. H. H. STIRRUP ON 



E. pellucidus He in the structure of the brain and sperm athecce. 

 The brain of E. albidus is definitely concave behind (PI. XLYI. 

 fig. 1), whilst that of E. pellucidus is rounded or convex behind 

 (fig. 2); but this is a variable character, according to the state of 

 tension of the worm, as I have seen the brain of E. albidus quite 

 straight behind with no concavity at all, and also the brain of 

 E. pellucidus with slight indications of a concavity behind. The 

 spermatheca of E. albidus has a definite rosette of glands around 

 the external opening of the duct (fig. 3), whilst E. pellucidics 

 is described as having no such glands. But the duct of the 

 spermatheca of E. pellucidus is irregular in outline, and in my 

 sections it is seen that these irregularities are due to simple 

 glands, which are not, however, in the form of a definite rosette 

 as in E. albidus. Again, the habitat of these two species is the 

 same, viz. old stable-manure and leaf-mould. In all other respects 

 they are very similar. 



Short Description of the most easily obse^'ved Characters of 

 E. pellucidus. — It is a white transparent worm, from 15 to 

 20 mm. in length. The number of segments varies, but is 

 usually about 60. The setae are straight with the innermost ends 

 slightly curved, giving them the appearance of hockey-sticks ; 

 the number of setae is not absolutely constant, but is usually 4 in 

 each bundle in front and 3 behind the clitellum. The brain is 

 twice as long as broad when stretched to the fullest extent, and 

 convex behind with pigment-spots at the posterior end. The 

 nerve-cord is equally broad throughout. tSalivary glands (pepto- 

 nephridia) are present ; they are not branched, but simply tubular 

 and slightly coiled or undulating ; the free ends are slightly 

 swollen. Blood colourless ; sperm-duct veiy long, often extends 

 10 or 12 segments behind the clitellum; it is internally ciliated 

 very strongly along its whole length. Spermathecae in segment 5 

 (external opening at intersegment 4/5), communicate with ali- 

 mentary canal ; ampulla large, filling up the whole of segment 5 ; 

 no rosette of glands around the external opening of the duct. 



Habitat. — My material of E. pellucidus was found abundantly 

 in a heap of refuse which consisted for the most part of leaf- 

 mould. In the heap were autumnal sweepings of leaves, grass cut 

 from the lawn, soil, stones, and occasionally bundles of soaked 

 brown paper. Although single worms were common throughout 

 the whole heap, I often came across large quantities of these 

 Enchytraeids quite unexpectedly. When I did so, these worms 

 always looked bigger and healthier, and a large percentage of 

 them was always mature. I have always been able to get mature 

 worms from this heap, whatever the month of the year ; this 

 points to the fact that they may be mature all the year round. 

 In the laboratory I kept the Enchytrajids in tin boxes with the 

 leaf-mould in which they were found. They lived quite well 

 here, but I always found , that the number of mature worms 



