222 THE ZOOLOGIST. 
elsewhere. I turn from the Tubificide to record certain Enchy- 
treids which are either new to England, Britain, or science. 
3. MaRIonIna sEmMIFusca, Clap., was first described from the 
Hebrides. It was afterwards found in Scotland and Ireland, but 
until the present year its occurrence in England had never been 
noted. I have, however, recently received some material from 
Purfleet, through the courtesy of Mr. C. S. Todd, and amongst 
other interesting species this occurs. It is straw-coloured, 
about 10 mm. in length, with 4-5 sete in front, and usually 3 
(rarely 2 or 4) behind. The brain, as is most usual in this 
group, is incised posteriorly, the funnels of the sperm duct are 
three to four times longer than broad, and there are large pores 
at the extremity of the duct. This same species, or one closely 
resembling it, was also found on the banks of the Gelt at Gils- 
land, Feb. 12th, 1912. The species of Marionina and Pachy- 
drilus (= Lumbricillus) so closely resemble each other that they 
need very careful study for their differentiation. 
4, Marionina RIPARIA, Bret.—This small annelid, first de- 
scribed by Bretscher in 1899, has been found by me hitherto 
but once only. I collected three examples in a little Derbyshire 
stream near Hartshorne at the end of 1911, and find they agree 
in all important details with the original description. Length, 
4-6 mm. Segments 28 asarule. Brain deeply incised behind, 
and slightly concave in front. Sete usually 3, sometimes 4, in 
each bundle in the anterior segments, and equal in length ; 
2 or 3 behind, long; none on the 12th or girdle segment. The 
intestine, as is frequent in Marionina, widens behind the girdle, 
and gives rise to the dorsal vessel. The ccelomic corpuscles 
are very large and striking, and the nephridia have a large 
postseptal. The ampulle were not clearly defined, though 
Bretscher gives them as three to four times longer than broad. 
I found a very long, coiled, slender duct attached thereto, but 
the presence of large numbers of ova obscured the organs here. 
There is a large heart in front of the girdle, and on segments 11 
and 138, preceding and following the girdle, two sete in each 
bundle. The vascular system shows the typical arrangement. 
Found also at Netherseal, Dec. 9th, 1911. 
5. ENcHYTRmUS HyaLiINus, Hisen.—It will take a long time 
to disentangle the different species of Enchytreus, and I am 
