116 MISS G. SWEET ON THE SPERMIDUCAL 
The two vasa deferentia of each side remain quite distinct, 
though close together after segment 13. They enter the spermi- 
ducal duct, which is curved into a U-shape, near its external 
opening on segment 18. Close by, and on the inner side of 
each duct, and only visible under the microscope, are a pair of 
small and thin sacs, each containing two (or sometimes three) 
very fine, smooth, and slightly curved penial setz, which open 
into the termination of the spermiducal duct by definite tubes 
lined with columuar cells. 
14. D. Baxurt * (Fletcher). 
Two pairs of testes and rosettes in segments 10 and 11. 
Sperm-sacs in segments 9 (posteriorly) and 12 (anteriorly). 
Spermiducal glands are tubular, somewhat coiled, and extend 
through four segments, 18 to 21 (fig. 1). The gland-duct is 
long and slightly curved, and very muscular. On the inner side 
of each duct is a pair of small sacs, each containing a penial seta 
surrounded by muscle-fibres. The division between the gland 
and the duct is more sharply marked than usual. The two vasa 
deferentia of each side join at the level of the prostate just 
before they enter the muscular wall of the duct, and so open 
into the duct itself at about half its length. Into the last 
portion of the spermiducal duct open by a pair of well-defined 
tubes the two penial sete, which are stouter than in D. Cope- 
land. 
VI. MrcaAscouex. 
15. M. Frencutt (Spencer). 
Two pairs of testes and rosettes in segments 10 and 11. 
Sperm-sacs in segment 9 (posteriorly) and segment 12 (ante- 
riorly). 
The spermiducal glands are flattened and bilobed, and are 
situated in segments 18 and 19, one lobe in each (fig. 8). The 
whole surface of the gland is divided up into irregular or 
polyhedral areas, which, as will be seen later, correspond with 
certain points of internal structure. The septum separating 
segments 18 and 19 is continued between the two lobes of the 
gland, and is pierced by the branch of the duct on its way to the 
main gland-duct. The main gland-duct, which is in segment 18, 
* Proc. Linn. Soc. N. S. W. ii. 1887, p. 616: Pericheta Bakeri (Fletcher). 
Beddard, Joc. cit. p. 440. 
_ + Proc. RB. 8. Vict. 1892, p. 9: Pericheta Frenchi (Spencer). Beddard, /oc. 
cit. p. 379. 
