52 ON THE ANATOMY OF MEGASCOLIDES AUSTRALIS, 
Fig. 7.—Section of epidermic cells, with the cuticle externally, in the region 
outside the clitellum. The inner ends of the cells pass down into the basement 
membrane (b.), and are not clearly defined. In the membrane lie scattered nuclei, and 
blood-vessels pass up amongst the bases of the cells, and sometimes form loops (not 
shown in the figure), which reach very close to the surface. Certain of the cells are 
transformed into large irregularly shaped goblet cells (gob.), the interior of which 
shows a granular protoplasm with vacuolar spaces, and usually a nucleus pushed to 
one side. Beneath the basement membrane lie the circular muscle fibres. 
Fig. 8.—Diagrammatic representation of one complete segment of the body, and 
a portion of another behind the 14th segment, to show the blood vascular system. 
The body wall is supposed to be completely removed, and the septa in position. The 
alimentary canal is represented as a simple tube, passing through the septa. Above 
it lies the dorsal blood-vessel (d. bv.) This gives off—(1) two vessels in each segment, 
one on either side, to the septum (set. bv.); (2) two pairs of vessels in each 
segment, one pair on either side, to the walls of the alimentary canal (al. bv.) 
Beneath the alimentary canal is the ventral blood-vessel (v. bv.), from which arises 
one branch on either side in the posterior part, supplying the anterior face of each 
septum. From this vessel a branch passes off on each side to the body wall, 
supplying the nephridia, &. The ventral blood-vessel, together with the nerve cord, 
passes through an opening in the septum ventrally, and from the nerve cord arise 
three branches on each side (w.’ n.? 1.) 
Fig. 9.—A similar representation of segments 12, 18, and 14, and part of 11. 
Segments 12 and 13 are alike, and show the development of the vascular system 
peculiar to segments 13-6 inclusive. The dorsal vessel is dilated, and gives off, mm the 
posterior part of the segment, a large vessel (/.), which runs round and joins the 
ventral vessel. This is muscular and dilatable, and forms the “heart.” From it arises 
a branch, which runs towards the dorsal wall of the alimentary canal, and divides into 
two. parts, of which one joins its fellow of the other side, and the two together form 
a single median vessel on the roof of the alimentary canal (a/.* bv.); the other runs 
downwards, and again divides into two, one of which joins a lateral blood-vessel at 
the side of the canal (/at. bv.), the other passes to the septum, and also gives branches 
to the body wall. No other branches beyond the “hearts” are in connection with 
the ventral blood-vessel in these segments. In the 14th segment the vessels are 
similar to those in the segments behind (cf. Fig. 8), with the exception that the 
lateral blood-vessel is continued into it, and lies by the side of the alimentary canal, 
without having any connection with the other vessels in the segment. 
By an unfortunate mistake, the two septal blood-vessels arising from the ventral 
blood-vessel posteriorly, just as in Fig. 8, have been omitted. These are present in 
every segment behind those in which the hearts are developed. 
