M. BOSC wrote, that he obtained his information from travellers to
the further east, and has connected with the habitat universally
ascribed to them from old KNOX'S work (Part 1. chap. vi.) a meagre
description, more properly belonging to the land leech of Batavia or
Japan. In all likelihood, therefore, there may be a _H. Boscii_,
distinct from the _H. Ceylanica_. That which is found in Ceylon is
round, a little flattened on the inferior surface, largest at the anal
extremity, thence gradually tapering forward, and with the anal sucker
composed of four rings, and wider in proportion than in other species.

[Illustration: EYES AND TEETH OF THE LAND LEECH OF CEYLON]

It is of a clear brown colour, with a yellow stripe the entire length of
each side, and a greenish dorsal one. The body is formed of 100 rings;
the eyes, of which there are five pairs, are placed in an arch on the
dorsal surface; the first four pairs occupying contiguous rings (thus
differing from the water-leeches, which have an unoccupied ring betwixt
the third and fourth); the fifth pair are located on the seventh ring,
two vacant rings intervening. To Mr. Thwaites, Director of the Botanic
Garden at Peradenia, who at my request examined their structure
minutely, I am indebted for the following most interesting particulars
respecting them. "I have been giving a little time to the examination of
the land leech. I find it to have five pairs of ocelli, the first four
seated on corresponding segments, and the posterior pair on the seventh
segment or ring, the fifth and sixth rings being eyeless (_fig_. A). The
mouth is very retractile, and the aperture is shaped as in ordinary
leeches. The serratures of the teeth, or rather the teeth themselves,
are very beautiful. Each of the three 'teeth,' or cutting instruments,
is principally muscular, the muscular body being very clearly seen. The
rounded edge in which the teeth are set appears to be cartilaginous in
structure; the teeth are very numerous, (_fig_. B); but some near the
base have a curious appendage, apparently (I have not yet made this out
quite satisfactorily) set upon one side. I have not yet been able to
detect the anal or sexual pores. The anal sucker seems to be formed of
four rings, and on each side above is a sort of crenated flesh-like
appendage. The tint of the common species is yellowish-brown or
snuff-coloured, streaked with black, with a yellow-greenish dorsal, and
another lateral line along i