294 DR J. STEPHENSON ON 
I have only a few remarks to make on the other systems. The alimentary canal 
is a fairly uniform tube throughout, showing little differentiation into distinct regions. 
The pharyngeal epithelium is markedly ciliated ; chloragogen cells begin in segment vi, 
and cease in the anterior gill region ; the canal becomes somewhat wider in segment xi, 
from which point it may be spoken of as intestine; the anus is dorsal. The ‘septal — 
glands,’ in segments iii, iv, and v, are collections of cells, not massed together in — 
definite lobes, but surrounding the alimentary tube on all sides in the posterior part of 
each of the three segments; the septa are here bulged backwards, and the funnel-shaped 
space so formed is filled with the cells (fig. 2, p). The glands are thus, apparently, 
merely collections of peritoneal cells. 
The nephridia are long, closely coiled tubes, with a pear-shaped reservoir near the 
external aperture; the reservoir is less marked in the posterior nephridia. ‘They begin’ 
in segment xii, and cease from fifteen to thirty segments in front of the posterior end; 
the external apertures are in line with, and in front of, the ventral setal bundles, near 
the anterior margin of each segment. 
The cerebral ganglion is deeply indented anteriorly, less so behind; the dora 
vessel, here divided, is closely applied to its under surface. The ventral nerve cord is” 
relatively very large in the posterior part of the body (fig. 5), and may be equal in 
diameter to the intestine; it is even absolutely larger than in the (much thicker) 
anterior part of the body; thus in one specimen, when sectioned, the transverse 
diameter of the cord was 61u anteriorly, 110u where the gills commenced, and 82m in 
the posterior gill region. 
Unfortunately none of my specimens were sexually mature. Testes were present 
in x, and ovaries in xi, and in one specimen the male deferent apparatus was beginning 
to form, in the shape of a funnel on septum 12, while a backward pouching of the same 
septum indicated the commencement of the vesicula seminalis; but there was nothing 
distinctive to be discovered. 
Iimnodrilus socialis, sp. nov. 
The mode of occurrence of this worm has already been described. On a subsequent 
occasion I found it even more abundantly in the same locality; the small pools were 
beginning to dry up, and the water was everywhere very foul; the worms occurred in 
large tangled masses of sometimes several pounds in weight, their tails waving as 
all the genital organs, having disappeared. ‘hus, in each of two batches of over fifty 
individuals, only four complete specimens were found. The worms nevertheless behaved 
as usual, waving their posterior ends, and contracting on being disturbed ; when isolated 
