54 DR J. STEPHENSON ON 
a constriction at the septum, and the lumen undergoes many and irreeular windings 
in the post-septal portion. I propose, therefore, to consider the present form as a new 
species, under the name Hnchytrzus nodosus.* 
It is interesting to note here again, as has already been done from the other side in 
the case of Lumbricillus viridis, indications of transition between the genus Enchy- 
treus and the Lumbricilline group. In the present case these are (1) the seta shown 
in fig. 8, b, with its double curvature, as opposed to the straight setee of Hnchytreus ; 
(2) the presence of small ‘copulatory glands’ in segments xiv. and xv.; and (3) the 
definite and single penial bulb. I have already referred to the importance assigned by 
Ersen to this structure, and to the fact that this author distinguishes two sub-families, 
the Lumbricillinee and Enchytreeinee, according to the presence of a single penial bulb, 
or its substitution by a number of separate ageregates of gland-cells. 
It seems doubtful whether the presence or absence of a penial bulb is of sufficient 
importance to serve as a basis for the distinction of sub-families, or even, perhaps, of 
genera. And it is interesting in this connection to compare MICHAELSEN’s figure (10) 
of the structures round the male genital aperture in Hnchytreus mobi ( = albidus), which 
shows that there is there a true “ penial bulb” surrounding the end of the vas deferens, 
such as is met with in Lumbricillus ; it is, however, of comparatively small size, and 
there are in addition separate ageregates of gland-cells on each side of the bulb. In 
other words, there is a condition intermediate between, or representing a combination of, 
those described by E1sen as characteristic of his two sub-families. 
Enchytreus dubius, n. sp. 
Found under stones, between tide-marks, at Wemyss Bay. While the majority of 
specimens of other species of Enchytreeids were sexually mature from May to July, in 
this case the greater number of specimens were without sexual organs. 
The animals showed a ereat tendency to curl up. In length they were half an inch 
(12 mm.) or less. In colour they were whitish ; examined with a lens they were only 
moderately translucent under pressure, and showed a considerable amount of white 
opacity in the middle region of the body along the borders of the alimentary canal, due 
to aggregations of coelomic corpuscles and chloragogen cells. The clitellar region was 
no more opaque than the rest of the body. 
Segments, forty-four. Prostomiwm rounded or very bluntly conical, with minute 
secondary projections. Head-pore between prostomium and first segment. 
The set are in four rows, two ventral and two lateral. With very rare exceptions, 
there are two sete per bundle throughout, except that ventral sete are always absent 
in segment xii. Both ventral and lateral setee are of the same shape, straight, with a 
* The FL. parvulus of Frienp (6, 7), is doubtfully identified by MicHantsen (11), with HL. argenteus. The data do 
not permit a detailed comparison of #. parvulus with the present form ; but the two would seem to differ, at any rate, 
in the numbers of the setee and shape of the cerebral ganglion, and less markedly in size and number of segments, 
