400 Mr. F. E. Beddard on the 
Dr. Horst, in the paper already quoted, entirely agrees with 
Baird’s identification of Megascolex with Pericheta, and 
naturally points out that the latter name must be cancelled, 
since Megascolex has a priority of fifteen years. Although the 
last-named author does not state his own reasons for this 
identification, but relies chiefly upon Baird’s authority, any one 
reading ‘empleton’s description would naturally think that 
the earthworm presented no points of generic difference from 
Pericheta; the distribution of the sete is not sufficiently 
peculiar to mark off the genus Megascolex from Pericheta, 
inasmuch as we know that a continuous ring of sete is not 
always found in species which would unhesitatingly be as- 
signed to the genus Perichwta. ‘The only other point in 
Templeton’s description, the account of the generative organs, 
might well be referred to the apertures of the male generative 
ducts upon the 18th segment and to genital papille, such as 
are frequently found in Pertcheta. 
None of the specimens in the British Museum nor the single 
specimen in the Edinburgh Museum had the clitellam fully 
developed, though in one specimen segments 13-19 showed a 
slightly different colour from the rest of the body, which is 
doubtless a trace of a clitellum in a condition of development 
or degeneration. The specimen in the Edinburgh Museum, 
which presents an interesting peculiarity to be described 
shortly, Dr. Traquair kindly allowed me to open, and I at once 
ascertained that it was identical with an earthworm recently 
described by myself* as new, under the name of Pleurocheta ; 
I was able to verify my description and to add some details 
as well as to make one or two corrections. ‘The specimen in 
the Oxford Museum had a fully developed clitellum, extending 
from the 13th to about the 20th segment, and therefore beyond 
the apertures of the male generative duct, which are in seg- 
ment 18. ‘This fact alone is amply sufficient to show that 
there can be no possibility of confounding this earthworm 
with Pericheta, seeing that in this latter genus, as is well 
known, the clitellum occupies certain segments anterior to the 
openings of the male generative ducts, which only agree with 
those of JMegascolex (as also of other genera, e. g. Ponto- 
drilus) in being situated upon the 18th segment and in being 
provided with a prostate gland. The absence of a fully deve- 
loped clitellum in the specimens of Megascolex contained in 
the national collection renders it, of course, more difficult to 
distinguish this genus from Pericheta, though a careful ex- 
amination even of these specimens, and with regard to exter- 
nal characters only, reveals at once certain points of difference. 
* Trans. Roy. Soc. Edinb. vol. xxx. pt. ii. 
