288 
SUMMARY Oh' CURRENT RESEARCHES RELATING TO 
Porifera. 
New Sponges.* * * § — Under the names of Spongilla moorei and Spongilla 
tanganyihse , Mr. Richard Evans describes two new sponges collected by 
Mr. J. E. S. Moore in Lake Tanganyika at a depth of 350 fathoms. The 
second species was represented merely by a fragment preserved in cor- 
rosive sublimate, and was therefore probably so like the preceding 
species in its external characters as not to be distinguished from it at 
the time of collection. Internally the differences are striking. Both 
species contained gemmules ; hence their inclusion in the family Spon- 
gillidse. Apart from the gemmules, the first species approaches the 
Chalinidae very nearly, and the author is inclined to regard the Spon- 
gillidae as an artificial family, which will probably be eliminated with 
the advance of knowledge. 
Protozoa. 
Protozoa of Illinois River and adjacent Lakes. f — Mr. A. Hempel 
has made a list of the Protozoa and Rotifers. found in the Illinois River 
and adjacent lakes at Havana, 111. In the list of Protozoa ninety-three 
species are recorded, one of which (Difflugia fra gosa) is here described 
for the first time. The most widely distributed form was Difflugia 
globulosa, which appeared at every sub-station, and was present in nearly 
every month of the year. One peculiar fact noted was the occurrence of 
a number of Rhizopods in the surface towings ; nine species of Arcella 
and Difflugia formed a frequent component in the catches. 
Galvanotaxis of Amoeba. :J — Dr. Sclioenichen has a brief note on this 
subject. Yerworn observed that when a constant electric current is 
passed through the water in which there are forms of Amoeba, these flow 
unerringly to the kathode. Comparing the retraction and protrusion of 
pseudopodia to the contraction and relaxation of muscle, Yerworn sup- 
posed that the current stimulated the amoeboid cell to contraction on the 
anode side, whereas nerves and muscles are stimulated toward the 
kathode side. On the other hand, F. Schenk has maintained that the 
comparison is illegitimate. The pseudopodia are retracted even with 
the minimum of stimulation ; they are protruded on moderate stimula- 
tion ; this depends largely on conditions of temperature. Experiments 
show that in warmed water the pseudopodia are protruded towards the 
anode end. In fact, the movements of the Amoeba cannot be readily 
brought into line as yet with muscle-contraction. “ There are per- 
haps not more unsuitable objects for the study of contraction than the 
Protists.’ , 
Conjugation in Vorticellids.§ — Herr IIs. Wallengren has studied 
the phenomena of conjugation in various species of Vorticella , and on 
Epistylis simulans Plate which lives on Asellus aquaticus. It is to the 
species of Epistylis that the author’s conclusions especially refer. The 
microgonidia do not seem to be so degenerate as Plate described them. 
There is a vestibular cavity with its ciliary apparatus, a well-developed 
* Quart Journ. Micr. Sci., xli (1899) pp. 471-88 (2 pis.), 
t Bull. Illinois State Lab. Nat. Hist., v. (1898) pp. 301-88. 
t Zeitschr. angewandt. Mikrosk., iv. (1898) pp. 201-2. 
§ Biol. Centralbl., xix. (1899) pp. 153-61 (3 figs.). 
