1102 REPORT—1885. 
4. Contributions to the Structure of the Oligocheta.1 
By Frank E. Bepparp, M.A., F.R.S.E. 
The present paper is a brief abstract of certain results obtained from the study 
of a number of different genera and species of earthworms lately received from 
New Zealand, the Philippine Islands, and the Cape Colony, through the kindness 
of Professor T. J. Parker, Mr. H. E. Barwell, and the Rey. G. R. Fisk. 
(1) Nephridia.—Perrier has called attention to a remarkable inconstancy in the 
position of the nephridial pores in different genera of earthworms. In Lumbricus’ 
and other genera the external pores are placed near to the more dorsal pair of sete 
in all the segments of the body; in Anteus the nephridial pores have a similar 
relation to the ventral pair of setae ; finally in Pontodrilus the nephridial aper- 
tures alternate in position from segment to segment, sometimes being placed by 
one of the dorsal, at other times by one of the ventral pair of sete. These facts 
seem to indicate the typical presence in earthworms of two series of nephridia 
each corresponding to one of the two pairs of setee—an hypothesis originally put 
forward by Lankester. Other earthworms besides Pontodrilus present this same 
alternation in the position of the nephridial pores; in two species of Acanthodrilus 
(A. novezelandiea, n. sp., A. dissimilis, u. sp.) the same series of facts were 
observed, but in these two species the dorsal and the ventral series of nephridia 
differed not merely in their position but also in their structure, which latter fact 
perhaps tends to still further support the hypothesis referred to above. The 
hypothesis of a single nephridium to each pair of setes may be true enough for 
those earthworms where the sete are disposed in pairs, but it is not sufficient to 
account for the relations of the nephridia described by Perrier in Pontodrilus. 
Here the sete are in eight nearly equidistant longitudinal rows, other nephridial 
pores alternate not only from pair to pair of setee but from seta to seta of each 
pair, seeming to be the remnant of a series of nephridia to each one of the sete. 
That this is really the case is proved by the structure of another Acanthodrilus 
(A. multiporus, n. sp.) where the sete are similarly disposed in eight longi- 
tudinal rows of single sete, to each of which corresponds a nephridial tube and 
external orifice ; in the anterior region of the body the nephridial tubules branch 
and open by a multitude of orifices forming a continuous ring round each segment 
between the sete. The presence of more than a single pair of nephridia to each 
segment has already been noticed by Eisig in certain Capitellidz, and the ducts 
have been stated by W. Fischer to branch in the same way that has been described 
in Acanthodrilus multiporus. 
(2) Spermathece.—The spermathece of earthworms are in some species, as in 
Lumbricus, simple spherical sacs; in other species they are furnished with one or 
more diverticula. Sometimes the diverticula come to open into the exterior in- 
dependent of the spermathecee, as in certain species of Pericheta. In Microcheta, 
a large worm from the Cape Colony, there are no spermathecz like those of other 
earthworms, but a number of minute pouches in four segments of the body, vary- 
ing from one to four. These appear to correspond to the accessory pouches or 
diverticula of other species, and are placed close to the nephridia of their seg- 
ments. They have in fact much the same relation to the nephridium as the 
diverticula of Pericheta aspergillum (Perrier) have to the spermathece, which is 
a further argument in favour of regarding the spermathecze as modified nephridia. 
In Acanthodrilus multiporus, novezelandia, and dissimilis, the spermathece are 
furnished with diverticula which vary in number, but are characteristic for the 
species. In every case these diverticula differ in their minute structure from the 
spermathece ; and the fact that they are invariably packed with spermatozoa 
while the spermathecze are as invariably devoid of spermatozoa indicates that. 
their share in the process of fecundation differs from that of the spermathece. 
(8) Dorsal Blood-vessel.—Dr. Vejdovsky has recorded the fact that in Crio- 
drilus the dorsal vessel originates from two rudiments which at first form two dis- 
tinct tubes and only subsequently coalesce. In certain earthworms the (presumably) 
1 See No. 238, Proc. Roy. Soc. 
