la i i 
Genus Megascolex of Templeton. 401 
In all the specimens, with one exception, the ventral surfaces 
of the 17th, 18th, and 19th segments are traversed by two 
thick glandular folds (the remnant of the clitellum), differing 
by a yellowish colour from the surrounding integument, 
and separated from each other by a space of about 7 inch: 
in the groove on the inner side of each of these folds are 
situated the male generative apertures and two papille; the 
former lie in the middle of the 18th segment, just in 
front of the row of sete which traverses it, whilst the latter 
are upon the boundary-line between segments 17-18 and 
18-19 respectively ; the rows of setes upon segments 17, 18, 
and 19 stop short at the outer edge of the glandular fold. 
Although it is well known that many species of Pericheta 
possess genital papille in the neighbourhood of the male 
genital apertures, an inspection of Perrier’s figures of these 
structures at once shows that they are not quite the same 
as those of Megascolex ; instead of being upon the boundary- 
line between two segments, they are quite in the middle 
of a segment in the region occupied by the row of sete. In 
one of the five specimens of Megascolex that are in the na- 
tional collection the male genital apertures and the papille, 
instead of being hidden away at the bottom of a deepish groove, 
are situated upon the upper surface of an oval longitudinal 
swelling which extends over exactly the same number of 
segments as the longitudinal fold. Upon the 13th segment 
are two apertures, which are most probably the external open- 
ings of the oviducts; like the male generative apertures they 
are placed just in front of the row of sete. The specimen 
in the Edinburgh Museum, which in other respects showed a 
perfect agreement with the five of Megascolex in the British 
Museum, has only a single oviducal aperture situated upon 
the middle of the ventral surface of the same segment and 
surrounded by a circular area differing somewhat in colour 
and appearance from the rest of the integument. 
With regard to the internal structure of Megascolex I have 
nothing to add to my former description, where the numerous 
differences between Megascolex aud Pericheta are indicated. 
I append a definition of the two genera. 
Pericu&TA, Schmarda. 
Pericheta, Schmarda, Neue wirbellose Thiere, 1861, Bd. i. 2. 
Megascolea, Baird, P. Z.S. 1869, p. 40. 
Pericheta, E. Perrier, Nouv. Arch. du Mus. 1872. 
Megascolex, Horst, Notes Leyden Museum, vol. y., note xvii. p. 182, 
Sete generally arranged in a continuous row round the 
middle of each segment; clitellum occupying 2, 3, or 4 seg- 
