CONTRIBUTIONS TO THE ANATOMY OF EARTHWORMS. 429 
The atrial pores are, as usual, situated upon the seventeenth 
and nineteenth segments on prominent papille corresponding 
in position to the sete 27 and 2/; a longitudinal groove, as in 
other species, connects the two orifices of each side. 
The external characters ally this species rather with 
Acanthodrilus multiporus than with A. nove-zealandize 
or A. dissimilis; the distribution of the setz and the 
characters of the prostomium are much the same; it differs in 
the less extent of the clitellum and in the fact that the papille 
upon which the atrial pores are borne are not so prominent 
as in A. multiporus; the prominent atrial papille are 
specially characteristic of A. multiporus and also of A. 
annectens. 
The internal anatomy of A. antarcticus shows numerous 
points of resemblance to A. multiporus, though there is no 
doubt as to its distinctness. 
Alimentary Tract.—The pharynx occupies the first four 
segments; there is a well-developed gizzard in segments vi and 
vit. In the fourteenth and fifteenth segments the walls of the 
cesophagus become much thickened; this dilated portion of 
the cesophagus probably represents the calciferous glands of 
other Earthworms; in A. multiporus these glands are found 
further back—in the seventeenth segment. 
I have studied the structure of these glands by transverse 
and longitudinal sections, It appears that they really represent 
two pairs of glands such as are found, for example, in A. 
dissimilis, but their apertures into the cesophagus are so 
large that the glands present the appearance of being little 
more than glandular dilatations of the cesophagus itself; in 
transverse sections, however, the epithelium of cesophagus can 
be here and there detected, and it is totally different from the 
epithelium of the glands; the cells are much more elongated, 
and are more deeply stained than the cells of the gland, 
by the reagent used (alum carmine); both the glandular 
cells and the epithelial lining of the esophagus are 
furnished with long cilia—a character which distinguishes 
the calciferous glands of this species from those of A. dissimilis, 
