OLIGOCHAHTA OF TROPICAL EASTERN AFRICA. 257 
course of the blood-vessel destined for the supply of the gland. 
It terminates abruptly in the calciferous gland. Iam not at 
all certain that these tubes really possess a lumen; it is at 
least very inconspicuous, and also the duct is not always so 
long as that represented in the figure quoted. The aperture 
into the gut of a second gland is shown in fig. 11. Here it 
will be seen the duct of the gland is excessively short, and it 
appears to become solid a very short distance from the point 
whence it arises from the gut. 
Concerning the nature of the peculiar tissue which makes up 
the greater part of the calciferous gland it is very difficult to 
speak positively. In several preparations from specimens 
which had been preserved with Perenyi’s solution, the layer of 
peritoneum surrounding the esophagus appeared to pass with- 
out a break into the tissue of the gland. The appearance of 
this tissue is, indeed, more suggestive of peritoneal cells than 
_ of epithelial cells derived from the intestine. On the other 
hand, sections of a worm that had been killed and preserved in 
gradually increasing strengths of alcohol did not show any 
such gradual passage as has been indicated, for in these sections 
the peritoneum clothing the intestine was coloured of a 
greenish tint, and there was a sharp demarcation between this 
tissue and that forming the bulk of the calciferous glands. Not- 
withstanding this fact, the tissue in question has more likeness 
to peritoneal than to any other tissue in the worm’s body. 
The only possible alternative, as it appears to me, is to assume 
that the cells have retained their embryonic state. In the 
embryo (not of this species, which is unknown, but of others) 
the cells of the mesenteron are charged with yolk spherules 
exactly like those in the gland tissue of the calciferous glands 
of the adult Stuhlmannia. The structure of the glands in 
this species is not very widely different from what I have 
described in Notykus (?) durbanensis in a paper recently 
published in the ‘ Zoological Society’s Proceedings’ (1892). 
It appeared to me, however, that the lumen of the glands in 
that worm were rather more developed than in Stuhlmannia, 
The lumen was quite obvious, though of little extent. The 
