132 MISS G. SWEET ON THE SPERMIDUCAL 
inferred that in the latter case it has not yet made its way to 
the cavity of the gland; while in the former it is just about to be 
passed out into that cavity, as the outer part of the cell in these 
cases is very finely granular, and does not take the methylene- 
blue at allreadily. The cells are much larger than those seen in 
other forms, and, by the irregularity in shape of their inner ends, 
they make the cavity of the gland in this region very uneven, 
though of greater calibre than the intermediate portion. The 
blood-vessel runs up alongside the wall of the gland and branches 
on the surface. It will be found that this differs considerably 
from the description given by Beddard of the spermiducal 
gland of Acanthodrilus among other genera. Acanthodrilus is 
described by him as being similar to other genera of Megasco- 
licide, such as those having tubular spermiducal glands, 
z. e. the Cryptodrilide and Perichetide, and all but one of the 
Acanthodrilide. That this is not so in this species is evident. 
In the first place, the cells of the columnar lining, even in 
the intermediate portion, are not granular, the nucleus only 
being generally visible, and indeed this is by no means a constant 
character in many of the genera, as before described. There 
is further no columnar-cell lining at all in the glandular part 
proper of this Acanthodrilid. Again, the glandular cells here 
are quite distinct in shape and appearance from the pear-shaped 
cells with long duct-like inner ends, found so constantly in such 
genera as Megascolides, Diporocheta, and the ordinary Acantho- 
drilids. They are here moreover only one layer thick. Even in 
the intermediate portion the gland-cells are more like those in the 
glandular part proper, than like those found in the genera above 
named. 
2. The Lobate Forms.—These show in microscopic section a 
distinct and characteristic lobular arrangement, typically without 
any central tube. The lobules are more or less well-defined 
accordingly as the whole gland is less or more compact, since in 
the more closely-packed glands the cells of contiguous lobules 
have a tendency to overlap, thus masking to a certain extent 
the radiate appearance so conspicuous in the looser forms. The 
lobules, especially in the latter case, are separated by a small 
amount of connective-tissue (P1].15. fig. 19). In this there run the 
blood-vessels of the gland (6.v.), which are often very numerous and 
definite, e.g. in Digaster brunneus, and at other times have more 
the nature of lacune; the very fine terminal branches of the 
