964 The American Naturalist. [October, 
throughout, collecting by the way many plants of interest to those less 
familiar with the central Indiana flora. 
The officers of the club for the next year are: President, Wm. M. 
Canby; Vice-President, L. M. Underwood ; Secretary, B. T. Gallo- 
way. 
Taken all in all, the botanists of the country have no need of feel- 
ing ashamed of the quality of the work done in the association and 
the related societies. —-CHARLEs E. BEssEy. 
ZOOLOGY. 
Heliotropism in Animals.—Groom and Loob! think that the 
daily migrations of pelagic marine animals are to be regarded as 
caused by heliotropism. In the day-time this is negative, the strong 
light driving them from the surface ; while at night it exercises a posi- 
tive action, causing them to seek the surface waters, Their observa- 
tions show that light, and not heat, is the exciting cause. Driesc 
finds that heliotropism influences the growth of the hydroid Sertulariella, 
Excretory Organs of Protozoa.—A. B. Griffiths states? that 
he has proved the existence of uric acid in the contractile vacuoles of 
Ameeba, Vorticella, and Paramecium. The Amceba was killed under 
the cover-glass with weak alcohol. This was followed by nitric acid, 
the slide warmed, and then ammonia was drawn under the cover-glass, 
the result being the formation of crystals of murexide in the contractile 
vacuole itself, as well as in its excretion. This clearly shows that these 
organs are for the excretion of nitrogenous waste. 
Note on Some Gigantic Specimens of Actinospherium 
eichhornii.—In a small pond near the observatory of the State Uni- 
versity of Iowa I collected some material which now stands on a table 
in the laboratory. Minute whitish discs, plainly visible, however, to 
the unaided eye, may be seen in considerable numbers clinging to the 
stems and leaves of Ceratophyllum. An examination of these discs 
reveals the fact that they are gigantic Rhizopods belonging to the 
genus Actinospherium, Actinospherium eichhornii they probably are, 
but they are vastly larger than any individuals of this species usually 
! Biol. Centralblatt., X., 160 and 219. 
* Zoolog. Jarbuch., V., p. 147. 
* Proc. Roy. Soc. Edinburgh, AVE, p. 131. 
