THE GIANT EARTH-WORM OF GIPPSLAND. 13 
towards both ends, and the duct passes right through the axis of the sphere (cf. for 
nephridia, plate 2, fie. 6, and plate 6, fig. 28.) 
From their relation to the alimentary canal, there is no doubt that they are of 
the nature of salivary glands, and their structure even to minute details shows them 
to be modified nephridia. The only difference observable between the salivary glands 
and the nephridia, is the absence in the former of the inter-cellular duct. The 
whole duct is intra-cellular until the epidermic lining of the pharynx is reached. 
This modification of nephridia agrees with that observed in Peripatus and almost 
certainly in Acanthodrilus multiporus and Trigaster lankestert.* It will doubtless be 
found to exist in many other worms. 
Segment five is occupied by the very short cesophagus, and the gizzard. The 
intestine commences in segment six, and runs hence to the extremity of the body. 
There is no trace whatever either of cesophageal glands or of typhlosole. The 
only modification in the intestine consists of very distinct dilatations in segments 
12-18 inclusive. (Figs. 3 and 4.) In these parts the walls are highly vascular, and 
devoid of any strong muscular development. Sections (Plate 5, fig. 24) show that 
the hypoblastic linme is thrown into a series of longitudinal folds. Each fold is 
made up of thin columnar cells with very distinct oval nuclei, the cells of each side of 
a fold being very close to each other, and separated by a network of blood-vessels 
(bv.) which are in connection with another network running round the intestine 
beneath the circular muscle fibres. This great supply of blood-vessels gives the 
dilatations of the intestines a reddish colour. Outside the blood-vessels lie (1) the 
layer of circular, and (2) the layer of longitudinal muscle fibres, both of which are 
comparatively feebly developed. In and amongst the latter is a small amount of 
connective tissue, and outside is the layer of flattened peritoneal epithelium cells. 
Posteriorly to segment 18 the intestine forms a simple tube, the walls of which 
are, as usual, brown coloured. In sections (Fig. 5) they are seen to have the usual 
structure. Most internally lies a layer of deep columnar cells with large spherical 
nuclei, each with a distinct aggregation of chromatin fragments in the centre. - There 
are no cilia to be seen, and when the walls are uncontracted the columnar cells form a 
smooth coating to the tube, with an absence of folds such as are described and figured 
by Bznyuam in Wicrocheta rappi. 
External to the columnar epithelium are the circular muscle fibres, which are 
well developed, especially in the posterior segments of the body, from which part the 
section represented is cut. Here, owing to the strength of the fibres, the canal 
retains its tubular shape when taken from the body. Externally to the circular, lie 
the longitudinal fibres (Long. M.), which seem to be best developed in the median 
dorsal line beneath the blood-vessel. In the walls of the intestine are two networks of 
blood-vessels. From the dorsal blood-vessel (Figs. 5 and 8, d. bv.) pass off two 
branches on each side of every segment to the walls of the alimentary canal. (Plate 
2, fig. 8, al, bv.) Hach pierces the longitudinal fibres, and a network of vessels is 
