282 
J. STEPHENSON, 
possibility, at least, of an extensive exchange between the 
cells and the body-cavity fluid. 
(c) The blood supply to the pharyngeal mass is extremely 
rich ; this is a striking feature in the dissection of any earth- 
worm in which the vessels of the anterior end of the body 
happen to be engorged. Not only so, but in all the species of 
Pheretima examined in the present paper, as well as in 
certain others, there are present, within and immediately 
behind the pharyngeal mass, large numbers of the structures 
known as “ blood-glands These are spherical bodies with 
an afferent and efferent vessel at opposite poles, containing 
blood, but largely choked by a mass of blood -cells. IIow 
widely these glands are distributed is not at present known ; 
of the many score of species of Pheretima, for example, 
by far the larger number have as yet only been examined 
from a systematic point of view. Blood-glands have been 
found in other genera of Megascolecidse also — in Acantho- 
drilus (Beddard, 1), in Pontodrilus (first by Perrier, cf. 
Eisen, 5), in Argilopliilns (=Plutellus, cf. Eisen, loc. 
cit.) — as well as in Spar ganophil us among the Greosco- 
lecidae (Eisen, 5) ; and they not improbably occur in other 
genera also, where they will be revealed by a fuller examina- 
tion than has yet been made. The situation of many of the 
smaller aggregates of chromophil cells on the blood-vessels in 
Helodrilus parvus may also be recalled in this connection. 
(d) That active metabolism takes place in the pharyngeal 
region is also indicated by the great development of the 
nephridial tubules, in micronephridial genera, in some of the 
most anterior segments. Here again we are dealing with a 
character which is not of systematic importance, and which 
has, therefore, seldom been recorded. Very noticeable 
bunches of nephridial tubes opening to the exterior occur at 
the sides of the pharynx in several species examined by 
Miss Raff (7a). Bushy tufts, sometimes of relatively very 
great size, and always in marked contrast to the minute 
scattered tubules of more posterior segments, occur at the 
sides of and immediately behind the pharyngeal mass in, for 
