320. ~©Friend: Enchytreids of the North of England. 
4. Henlea rosai Bretscher. This worm was first described 
in 1899, in time to be included in ‘ Das Tierreich,’ p. 70, where 
the description may be found. I discovered it for the first time 
on May 27th, 1911, at Buxton, in company with Enchytreus 
minimus Bretscher. My notes are as follows :—Rather larger 
than E. minimus, possessing 35 segments, pellucid, with brown 
intestine, which is sharply marked off from oesophagus in the 
seventh segment, where the chloragogen cells begin. Three 
pairs of septal glands, no oesophageal glands, pulsating vessel 
in the seventh and adjoining segments. Ampulla or funnel of 
sperm-duct, which is found with the girdle in segments XI. and 
XII., about twice as long as broad. First nephridia in 6/7, 
the duct passing out from the posterior portion. The sperm- 
athecee composed of a simple duct, without diverticula or glands. 
There may be an enlargement or swelling of the duct about the 
middle, or not. The brain is rather broader than long (my 
camera lucida drawings give the ratio 18:15), concave in 
front and convex behind. 
Found among vegetable debris by a wall in the Serpentine 
Walks, Buxton. 
5. Henlea perpusilla Friend. On July 9th, rorr, I collected 
some alluvium from a ditch near Cauldwell, some four or five 
miles from Ashby-de-la-Zouch and Burton-on-Trent. It proved 
to be rich in Enchytreeids of the minuter kinds, and yielded a 
species of Henlea which had not, so far as I can discover, been 
previously described. In a few points it is of peculiar interest. 
I examined several specimens with great care, and found certain 
variations which seem to be always occurring in this variable 
group. Thus, while there was always a pair of nephridia in 6/7, 
I found in one instance that the first pair occurred in 5/6. 
Again, these organs differ in shape and arrangement. In the 
anterior portion of the body the duct springs near the septum, 
while the hinder portions of the worm shew the duct of the 
nephridia passing out from the rounded posterior. This indi- 
cates the importance of noticing the structure of organs at 
different points. There is probably some bionomic as well as 
taxonomic value in the difference. I have carefully noted and 
drawn the sete of the head and tail, since these also vary as 
much as the nephridia do. They vary in number from three to 
six, very rarely seven or eight ; and in front the ventral bundles 
usually have one more seta than the lateral. Here are the 
numbers as found in a typical specimen :— 
SET® FROM HEAD OF H. perpusilla FRIEND. 
Segment. Lateral. Ventral. 
Ble i 3.4 ‘o 4.5 
rite 4.4 ‘< 525 
IV. 3.4 5.6 
V. 4 4.6 
Naturalits, 
