492 MR. F. E. BEDDARD ON THE 
considerably the narrower of the two; its diameter is about 4 of that of the 
large intestine (see Plate X XV. figs. 1, 7), and its walls, at any rate in the first 
portion, where it is attached to the thick mesenteries already described, are 
stouter. In the 16th segment commences the large intestine quite suddenly, 
there being no transition between it and the small intestine. The large 
intestine extends from the 16th segment to the end of the body, with no 
alteration in size. When the intestine was first opened, the contents, consisting 
of earth, vegetable débris, &c., showed a marked dissimilarity in colour ; in the 
anterior half the contents were ofa pale yellowish colour, in the posterior half, of 
arich and dark greenish-brown tint ; this is no doubt owing to the fact that the 
glandular development of the posterior half of the large intestine is far greater; 
the intestine itself showed no signs of a typhlosole, and in this structural 
peculiarity Plewrocheta resembles Pontodrilus, the only remnant of the 
typhlosole being in these two forms the supra-intestinal vessel; in Pericheta 
and Urocheta also the typhlosole is very much simplified. In the first six 
segments occupied by the large intestine the glandular epithelium is chiefly 
developed in a double series of shallow dorsal pouches in lines running across 
them at right angles to the long axis of the intestine. The gland cells examined 
were large, and appeared to be loaded with the products of their secretion in 
in the form of yellow granules ; at the 22nd segment the dorsal pouches become 
deeper ; they are still arranged in pairs, one pair to each segment on either side 
of the median dorsal line ; these pouches extend as far as the 44th segment (see 
Plate XXV. fig. 1) or thereabout, and are eminently glandular. In the first 
fourteen sets of pouches (7.¢., from the 22nd to 36th segmeuts inclusive) there is 
developed on the septum dividing each pouch from the one following it a folded 
membrane, covered with large glandular cells altogether similar to those 
described, which extends down the side of the septum. After these comes 
another set of pouches forming a continuation of the series, but with the 
glandular substance arranged differently ; each pouch contains eight or nine folds 
of a dark brown colour, extending right across it from the posterior to the 
anterior septum, presenting very much the appearance of a fish’s gill; there are 
from six to eight pairs of these pouches. Beneath the dorsal blood-vessel is a 
longitudinal fibrous band running along the course of the intestine, and above 
the supra-nervian vessel, on the ventral surface of the intestine, is another fibrous 
tract. The pouches are arranged on either side of the dorsal fibrous band, 
and deepen gradually from the middle line outwards ; in the region of the six 
posterior pouches there is an additional pair of fibrous bands developed on either 
side of the ventral band (see Plate X XV. fig. 8). Nothing like this has been 
to my knowledge described in any other Oligochetous worm. In the first part 
of the large intestine (down to about the 76th segment), which includes the 
region occupied by these pouches, the glandular development is very feeble, the 
