THE LEECHES OF JAPAN. 381 
width of the body. The marginal papillee are very close to the 
edge of the body, and nearly as large as the lateral papille. 
Colour.—The ventral side is a bright reddish brown, with a 
few small scattered flecks of black. The ground-colour of the 
dorsal side is dark olive green. The most conspicuous markings 
of this side are the median row of orange-coloured spots. The 
first of these spots forms an elongated patch, beginning on the 
Ist annulus and stretching back to the 5th. The hind end of 
this patch is almost constricted off, so that it sometimes appears 
to represent an independent spot. The entire patch can be 
regarded as four coalesced spots. Behind this there are twenty 
of these spots, one on each papillate annulus as far as the 98th. 
The 100th annulus had no orange spot in any of the speci- 
mens examined, but it does have it in some other species. 
These spots have an elongated form, except when the Leech 
is much contracted, each one stretching across a papillate 
annulus and a half or more of the annulus following. The 
elongation in an antero-posterior direction suggests that they 
are remnants of a median stripe, which was once continuous 
over the non-papillate as well as the papillate annuli. The 
presence of small flecks of yellow scattered sparingly along 
the median line can be most naturally explained on this hypo- 
thesis. Small dark flecks are thickly strewn along the median 
dorsal area; and these are perceptibly darker on each side of 
the orange spots, which may be taken as an indication that the 
hypothetical median stripe had dark borders. 
The next most prominent markings are two rows of quad- 
rangular black spots (6), one on each side, considerably nearer 
the margin than the median line. These spots lie between the 
lateral papille of each side, and are limited, for the most part 
to the papillate annuli; occasionally, however, they show a 
posterior elongation, more rarely an anterior one. 
Just inside the black spots there is, on each side, a row of 
faded black spots, irregular in shape, and plainly forming parts 
of an obsolescent dark stripe. 
The very narrow margins of the dorsal surface have the 
colour of the ventral side. 
VOL, XXVI, PART 3,—NEW SER, CG 
