350 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
supposed, a synonym of E. polymorplius Brems. Externally they may 
be distinguished by the smaller size of the latter, and its constant orange- 
red colour, while the female of E. Jilicollis is yellowish-white and the 
male whitish. There are also important internal differences. 
y. Platyhelminthes. 
Connecting Canal between Oviduct and Intestine in Monogenetic 
Trematodes.* — Mr. S. Gote is able to confirm the statement of Ijima 
that a peculiar canal connects the oviduct with the intestine in some 
ectoparasitic Trematodes. The canal which Zeller calls Laurer's canal 
in Diplozoon is evidently this structure ; the vas deferens of one individual 
of this twin-form distinctly opens into the volk-duct of the other. 
The Holostomidse.f — Dr. G. Brandes gives a monographic account of 
this family of Trematodes, the known species of which are not very numer- 
ous. They are all characterized by the presence, below the ventral sucker, 
of a structure which divides the body into an anterior and a posterior region. 
The simplest form is that of a lamella ; in some the anterior end becomes 
spoon-shaped, and this passes through various stages of complication to 
that of a cup. The anterior and posterior halves of the body are very 
rarely set in the same plane. 
With regard to the food of these internal worms there is reason to 
suppose that they are not simply contented with what falls from the 
plate of their host, but that they are aggressively parasitic ; they are not 
confined to the small intestine, but are also found in the rectum and 
bursa Fabricii, where the supply of food is not so abundant. The posses- 
sion by them of holding organs supports this view. In, for example, 
Hemistomum cordatum , a parasite of the wild cat of Brazil, the ventral 
sucker is greatly reduced, but an attaching apparatus is enormously 
developed, and has connected with it a complex of glands. This 
attaching organ may be formed on one of two types, both of which are 
described in detail. The digestive organs are also described. 
The male and female organs are united in the same individual, and 
the whole generative apparatus is characterized by the position of the 
efferent ducts at the hinder end of the body, while the uterus is only 
slightly coiled. 
Less constant characters are the position of the ovary between the 
two testes, and the separate course of the duct of Laurer. The whole 
generative apparatus is always placed in the hinder part of the body. 
Here, again, full details are given. Some additions are made to our 
knowledge of the water-vascular system. 
No previous author seems to have reported on the nervous system of 
these worms. In young stages of Hemistomum Dr. Brandes has, after 
treatment with osmic acid, seen the central mass of the nervous system 
lying on the lower part of the pharynx. Inferiorly two strong processes 
could be traced for some distance, while superiorly there branched off a 
pair of very short and delicate processes. In sections nervous elements 
have been observed in the parenchyma of the anterior end of the body. 
* Zool. Anzeig., xiv. (1891) pp. 103-4. 
f Zool. Jahrb. (Abth. f. Systematik &c.), v (1890) pp. 549-604 (3 pis.). 
