292 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
proboscis nerves. A few elongated subepithelial gland-cells occur in 
the head region. Numerous small ocelli lie behind the brain on the 
dorsal and lateral aspects of the lateral nerve-cords. On these grounds 
this form has been separated from Ampliiporus. 
Mr. Montgomery also describes Proneurotes multioculatus g. et sp. n. 
The lateral nerve-cords unite posteriorly below the intestine about 1 mm. 
from the hind end ; both rhynchoccel and blood-vessels are continued for 
some distance behind the nerve-commissure, a condition which occurs in 
no other Metanemertean. Very characteristic are five unpaired diver- 
ticula of the voluminous rhynchocoel. It is otherwise, except in the 
very small size of its blood-vessels, related to Amphiporus. The author 
next describes Amphiporus greenmani sp. n., Tetrastemma jlagellatum 
sp. n., and has notes on some other forms which are not new. 
Nephridia of Stichostemma.* — Dr. T. H. Montgomery finds that the 
nephridia of Stichostemma eilhardi are very aberrant. Instead of one 
j)air there are several pairs, from the anterior to the posterior end, but 
all have not ducts. Other peculiarities are the following : The terminal 
bulbs have a closed cavity, not in open communication with the lumen 
of the ductules ; the presence of a closed cuticular structure immediately 
surrounding the cavity of the bulb, produced probably by the cells of the 
latter ; the probable absence of a ciliary flame within the cavity of the 
bulb ; the comparatively great length of the ductule connecting the bulb 
with the main ducts, and the absence of nuclei in its walls ; and the 
presence of a cuticula, of considerable thickness, on the epithelium of 
the main ducts. 
The explanation of these remarkable differences can probably be given 
only in terms of the adaptation of this descendant of marine ancestors 
to a life in fresh water. The occurrence of numerous separate nephridia 
cannot be regarded otherwise than as a secondary condition in Nemer- 
teans. 
Species of Ophryocotyle.f — Prof. A. Villot corrects some of the 
previous descriptions of this genus. The triple series of hooks is 
situated on the anterior margin of the sucker ; there are jive frontal 
suckers ; there may be over a hundred proglottides. As to species : — 
0 . proteus is quite distinct from 0 . Lacazei , but 0 . insignis Lonnberg 
is synonymous with 0 . Lacazei. 
Trematodes of Freshwater Fishes.}: — Herr L. Hausmann has 
studied these in their faunistic and bionoinic relations. The following 
are some of his general conclusions. All kinds of fishes, whether vege- 
tarian or carnivorous, may be hosts of Trematodes ; but the carnivorous 
forms contain the sexually mature stages, the vegetarian forms usually 
the immature stages only, while those which live on microscopic animals 
may contain both stages. The number of parasites varies with the time 
of year, diminishing, for instance, in the cold season, when the fishes eat 
little. There are also fewer during the spawning season when the 
nutrition is slight. When a fish is brought into conditions of captivity, 
it tends to lose its parasites. The prevalent parasites vary somewhat 
* Zool. Jahrb. (Abtli. Anat.), x. (1897) pp. 265-76 (1 pi). 
t Zool. Anzeig., xx. (1897) pp. 197-9. 
% Rev. Suisse Zool., v. (1897) pp. 1-42 (1 pi.). 
