STRUCTURE OF THREE NEW SPECIES OF EARTHWORMS. 117 
Typhous. 
Generic Definition. — Setae paired aud confined to the 
ventral half of the body ; dorsal pores present ; clitellum 
developed upon segments 13 — 17. Male genital pores (in- 
traclitellian) upon seventeenth segment corresponding with 
ventral pair of setae. A single pair of spermathecae, each 
furnished with two trifid diverticula, opening between segments 
7 and 8 on a line with interspace between dorsal and ventral 
pairs of setae. A single pair of testes in segment 10 ; a single 
pair of vesiculae seminales enclosing testes and funnels of vasa 
deferentia, and reaching back for three or four segments. A 
single pair of vasa deferentia, each opening in common with, 
or close to, a coiled tubular atrium like that of Acantho- 
drilus ; penial setae present. Ovaries and oviducts occupying 
the usual position in the thirteenth and fourteenth segments ; 
gizzard single, intestine furnished with six or seven pairs of 
glands on the dorsal surface. Nephridia forming incon- 
spicuous tufts, nephridiopores of each segment numerous. 
T. Gammii. — Penial seta with wavy ridges round distal 
portion. Genital papillae two, on boundary line between seg- 
ments 19 — 20, 20 — 21. 
T. orientalis. — Penial setae with distal extremity flattened 
and furnished with chevron-shaped ridges. Genital papillae 
six or seven pairs between the several segments, immediately 
following and preceding the seventeenth. 
On the Structure and Homologies of the so called 
Prostate Glands in the Oligoch^ta. 
In certain Earthworks the vasa deferentia are unprovided 
at their external orifice with any glands; this is the case, for 
example, with Lumbricus, Urochaeta, and Microchaeta. 
In other genera glands are present, which either pour their 
secretion into the terminal region of the vas deferens, or else 
open on to the exterior independently, but in the immediate 
neighbourhood of the male generative pores; Perichaeta and 
Pontodrilus are instances of the former condition, while in 
VOL. XXIX, FART 2. NEW SLR. 
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