132 
ME. H. 1ST. MOSELEY ON THE ANATOMY AND 
The interior of the digestive tract is clothed with a thick glandular investment, which 
varies slightly in its structure in the various regions of the body. In the region of the 
mouth, the lining of the main digestive tract consists of peculiar rounded bodies arranged 
irregularly in rows at right angles to the surface, and gathered into elongated groups, 
so as to have a certain resemblance to the gastric glands of vertebrates (Plate XV. fig. 15). 
These rounded bodies are imbedded in a finely granular matrix. The glandular lining 
of the diverticula is made up of rounded or pear-shaped elements, with finely granular 
contents and occasional nuclear bodies; and in places these cells are distended into large 
transparent sacs with nuclei, and they then closely resemble those which form the glan- 
dular cells of the digestive tract of Planaria torva, which are figured in Plate XV. fig. 14. 
The lining of the caeca is much thinner than that of the main antero-posterior digestive 
tubes. The lining of these latter always partakes more or less of the form displayed in 
Plate XV. fig. 15, although that structure is best marked in the neighbourhood of the 
mouth. The glandular lining in the diverticula is often, especially in the head, tinged 
with a brown pigment ; and it is highly probable that these diverticula discharge a 
function somewhat like that of the hepatic tubes of Annelids, whilst the glandular lining 
of the main tract has a gastric function. I found no traces of vegetable matter in the 
digestive tracts of any of the many specimens of Bipalium and Bhynchodemus examined 
by me, nor, indeed, any distinctly recognizable foreign body at all. The digestive tube 
close to the mouth, in one specimen of B. Ceres , contained a mass of apparently animal 
matter ; but it was so far decomposed or digested that I could not determine its exact 
nature. The diverticula of both Bipalium and Bhynchodemus contain numerous grega- 
riniform parasites, which are also to be found imbedded in the neighbouring tissue: 
hardly any diverticulum is free from them, and they are usually massed together at the 
blind ends of the diverticula. 
Water-vascular System. — In vertical sections of the body of Bipalium and Bhyncho- 
demus, , such as those figured on Plate X., there are to be seen a pair of rounded spaces 
lying one on each side of a region immediately above the ambulacral line, and thrown 
out into relief by the fact that they are always very little tinged with the carmine- 
staining fluid. In Bipalium these spaces are separate, but in Bhynchodemus they are 
connected by a broad transverse tract ; and when sections of this animal are viewed under 
the microscope, the resulting figure, resembling somewhat a pair of spectacles in shape, 
is the most striking feature of the preparation. The spaces are irregularly oval in form, 
with the long axis of their figure directed transversely ; and throughout the entire length 
of the body they present nearly the same figure on section, except in the region of the 
pharynx and generative organs, where they are necessarily somewhat contracted. The 
spaces bear a constant relation in position to the oviduct and testis in the anterior 
portion of the body. The oviducts lie, in Bipalium Diana , B. Proserpina , and Bhyn- 
chodemus Thwaitesii, just above the space on each side, somewhat exteriorly to its middle 
line ; whilst in Bipalium Ceres they lie just within the space itself, but in the same region 
as in B. Diana. The testes in all these species lie just externally to the spaces on each 
