SOME LITTORAL OLIGOCH ATA OF THE CLYDE. 4] 
The cerebral ganglion is rather longer than broad, indented posteriorly but not 
anteriorly ; two small dark dots are to be seen, one on each side, in its posterior part 
(cf. Enchytreus albidus). Ganglionic swellings are well marked in the anterior portion 
of the ventral cord, but some distance behind the genital segments they become 
scarcely noticeable, the nerve cells being distributed over the whole length of the cord. 
The cord encloses a “ central canal.” 
The “ copulatory glands” are present in segments xiil. and xiv. as conspicuous lobed 
masses around the ventral cord, their centre at a level just posterior to the insertion of 
the setze (Pl. I. fig. 4). Hach gland consists of a mass of large cells, spherical, pear- 
shaped, or polygonal, which is situated ventral to and on each side of the cord. These 
cells do not quite meet above the cord, but, connecting those of one side with those 
of the other over the dorsal surface of the cord, there appears in sections a deeply 
staining band. The dorsal surface of the cord is indented between the cells of the two 
sides in the middle line. 
The glands are attached to the ventral body-wall by an almost homogeneous stalk ; 
the circular muscular coat appears interrupted at intervals along the area of attachment 
(the fibres being presumably displaced), so that the stalk of the gland seems here to 
fuse with the epidermis. The body of a number of these cells stains very lightly, and 
shows an appearance something like that of an empty reticulum; the nuclei of the 
gland-cells stain evenly ; those of the nerve ganglion cells which immediately surround 
the cord show, on the contrary, a number of distinct granules of chromatic material. 
The testes form a bunch of pear-shaped masses, attached by their narrow ends to 
septum +2; they shift with the movements of the worm, appearing now on one side, 
now on the other side of the septum. Their products get forward into segment viii., 
and fill seements ix. and x, 
The sperm funnels may be as much as nine times as long as broad. They are, 
however, here as in other species very contractile, and may shorten (e.g. on teasing) 
to as little as twice as long as broad. Hven in the body they may appear only about 
four times as long as broad, and vary. The vas deferens does not extend posteriorly 
beyond the clitellum ; it forms a fairly small coil, equal when uncoiled to about half 
a dozen segments; it has a fine lumen, in which, in teased specimens, active ciliation 
can be seen to be going on. The male apertures appear as semicircular fissures, 
convex towards the middle line. The pensal bulb is a spherical mass of considerable 
size, its diameter about a quarter of the whole diameter of the body ; the vas deferens 
penetrates the bulb laterally to its centre; the bulb is attached to the body-wall by 
a strand of tissue which passes dorso-laterally upwards from the upper surface of 
the mass. 
The ovaries are on the posterior face of septum +3; ova are found as far forwards 
as segment vii., and backwards far behind the clitellum. 
The spermathecal apparatus in the living animal consists of a somewhat spindle- - 
shaped mass, in which ampulla and duct are not to be distinguished; a mass of 
