THE LEECHES OF JAPAN. 351 
buccal; the fifth pair on the 8th annulus, or second post- 
buccal (fig. 10). 
(sophagus has six folds. 
Maxilla three, armed with from sixty to seventy straight, 
conical denticles. 
Nephridia, seventeen pairs. The first pair is located in 
the 6th somite, the seventeenth pair in the 22nd somite. The 
nephridial pores are placed on the ventral side in the posterior 
edge of the last annulus of each somite. These pores then 
occur in the following rings: the 13th, 18th, 23rd, 28th, 33rd, 
38th, 43rd, 48th, 58rd, 58th, 63rd, 68th, 73rd, 78th, 85rd, 
88th, and 93rd. There are thus four pairs of nephridia before 
the male orifice. 
The vesicles are oval sacs, measuring in sections of hard- 
ened specimens 0°8 mm. by 0°6 mm., and bridging only two 
rings. The three pairs of vesicles situated in the clitellum do 
not appear to differ in any respect from the rest. 
Segmental Papillew. — Beginning with the 5th ring, 
which bears the fourth pair of eyes, we find twenty-two 
papillate rings, in the following order,—5th, 8th, 11th, 14th, 
19th, 24th, 29th, 34th, 39th, 44th, 49th, 54th, 59th, 64th, 
69th, 74th, 79th, 84th, 89th, 94th, 97th, and 99th. Traces of 
these papille are seen also on the 101st. The dorsal side of 
each of these annuli, if we except the 5th and the 101st, bears 
six minute papille, a median pair and two lateral pairs. 
Possibly there may be a marginal papilla on each side, in 
addition to these, but none was recognised. As these papille 
are regularly placed on every fifth ring, except near the ends, 
where the intervals are reduced, they may be said to form six 
longitudinal rows (Pl. XVIII, fig. 10). These papille are quite 
conspicuous in fig. 18, as in this exceptionally coloured speci- 
men each is encircled by a ring of dark brown—a little darker 
than the pigment of the brown stripes. The area or spot thus 
encircled is dusky yellow, and shows at the centre a minute 
round dot that is entirely free from pigment. The papille are 
minute and project only slightly, and the circular areas which 
they occupy appear as mere pigment spots to the naked eye. 
