STUDLES ON EARTHWORMS. 261 
elongated “ prostate” (which Perrier calls ‘‘ seminal vesicle”’). 
Beddard has shown similar sacs of modified setee in Typhzus 
and Pericheta (Megascolex) armata (?7). 
In Pericheta and Perionyx~  vstate is present in the 
form of a more or less lobed or incised gland, opening by a duct 
into the sperm duct, whilst Moniligaster, Pontodrilus, 
and Plutellus have a tongue-shaped prostate similarly situated, 
and the common duct is muscular, curved, and probably pro- 
trusible. 
In Pleurocheta each of two pores in somite xvrit leads 
into a solid white gland, which from its position appears to be 
a prostate. 
The male pore is situated, usually, about the somite xvir or 
xvii, but in Lumbricus it is in somite xv. As has been 
mentioned above, the relation of this pore to the clitellum is 
used to group the Earthworms, and the absence or presence of 
papillz at or near these pores may be used to subdivide some 
of the genera. Lumbricus has its pores on wide but not 
prominent papille. 
In most Perichetz there are similar copulatory papille. 
Thus, in P. robusta a pair of papill are placed on somite 
xvi11 between the male pores. P. affinis has the male pores 
on papille, as well as a pair of papille in somite xvi and a 
pair in somite xix. In P. aspergillum the papille carry, 
besides the male pores, numerous smaller pores corresponding 
to small, internal, globular sacs. Similarly, round the pores of 
the spermathecz (in this species) are other pores opening into 
sacs internally. ; 
In P. Houlleti, quadragenaria, and elongata no copu- 
latory papillz are described. 
In Megascolex sylvestris (Hutton) the male pore is in 
somite XIx. 
In Perionyx, Pontodrilus, and Pleurocheta the pores 
are situated in pits in somite xvsi1, which in the case of 
Perionyx are close together near the middle line, and not, as 
usual, latero-ventrally. In Typhzus the male pore is in 
somite xvii, and copulatory papille are present. In Rhino- 
