174 
ZOOLOGY OF THE FAR EAST. 
by a narrow space perforating the mass vertically. In the neck region, where the 
body is very narrow, the nerve-mass appears as enormous, occupying almost the 
whole space within the body- wall. In short, the nervous system is well developed 
and exhibits even a higher degree of specialization than in the forms from shallow 
water. 
On the connective tissue and muscular system I have nothing particular to men- 
tion, as they dififer from those of other Glossiphonids only in detail. 
Locality. Lake Biwa, Sta. 8; depth about 260 Japanese feet; bottom, mud with 
fragments of shell. Oct. 1-3, 1915. Four specimens. 
Systematic Position. As is evident from the above account of the internal 
organization, this leech is more closely allied to the Glossiphonids than to any other, 
so that it has to be included unquestionably in this family. The resemblance to 
Ichthyobdellidae, which is so striking at the first sight, is confined to external char- 
acters alone, such as the general shape of the body, the appearance of the integument, 
etc. Of the internal organs, it is chiefly the lacunar system which characterizes this 
genus as a Glossiphonid ; namely, it has no lateral sinuses with muscular walls, the 
so-called lateral blood vessels, which are never wanting in the Ichth5^obdellidae. The 
structure of the generative organs, too, points to an alliance of this worm with the 
Glossiphonids, there being no such complicated parts, as are usually met with in 
Ichthyobdellids. The configuration of the alimentary canal is also of the Glossiphonid 
type. In short, in every S3'stem of organs we have evidences of its being a modified 
Glossiphonid. Within the family, however, it occupies a rather isolated position on 
account of its remarkably different shape of the body, the presence of hooks on the 
proboscis, the small number of nephridia, and many other characters which separate 
it widely from all other genera hitherto described . 
As another example of a Glossiphonid resembling an Ichthyobdellid in external 
appearance may be mentioned the American genus Actinohdella , Moore (1908, 1906), 
with the species inequiannulata and annectens. They are very small leeches measur- 
ing only 9-12 mm. in length, and look so unlike ordinary Glossiphonids that the 
first named species was published as belonging to the family Ichthyobdellidae. The 
body is elongated but more depressed; in contrast to the present genus, there are 
two large eyes, and the somites are six-ringed in the greater part of the body. Their 
mode of life is not known, but very probably they are blood-suckers. One example 
of A. inequiannulata was pumped from the bottom of Lake Pepin, Minnesota. I 
refer to this genus .simply to show that Ancyrohdella is not the only Glossiphonid 
which is likely to be mistaken for an Ichthyobdellid if superficially examined. 
14. Ozobranchus jantseanus, Oka (1912). 
Localities, (i) Near Moo- Too. Dec. i, 1915. Five specimens. (2) Tong-Dong- 
Ding, Tai-Hu, near Soo-chow. Dec. 4, 1915. Nine specimens. "On Damoniu 
reeve sii." 
These specimens differ somewhat strikingly from the type, as they have numer- 
ous dark brown conical papillae on the dorsal surface which are not found in the 
