212 



SCIENCE. 



[N. S. Vol. XIX. No. 475. 



the writer reviewed his work on the horned 

 dace and showed instantaneous photo- 

 graphs of the spawning fish. He described 

 further the breeding habits of the common 

 shiner, in which the function of the pearl 

 organs is essentially the same as in the 

 horned dace. He described also the breed- 

 ing habits of the back sucker. In this 

 form the spine-like pearl organs occur in 

 rows on the lower half of the sides of the 

 tail and on the enlarged anal of the male. 

 In spawning the female is held by two 

 males, one on either side of her. The 

 rough anals and caudals of the two males 

 press against the sides of the body and tail 

 of the female, and hold her in place. They 

 also press against one another beneath and 

 behind the female, and thus hold the two 

 males side by side. Spawning is accom- 

 plished by a rapid vibration of the tails 

 of the three fishes, and during the act the 

 eggs and milt are emitted and mingled 

 with the sand and gravel which have been 

 stirred up. 



Phototaxis in Banatra: S. J. Holmes, Uni- 

 versity of Michigan. 



Banatra shows under ordinary circum- 

 stances a marked positive phototaxis. In- 

 dividuals when in the water keep swim- 

 ming vigorously for a long time in the 

 endeavor to go towards the lightest portion 

 of their environment. When taken out of 

 the water Banatras at first feign death, 

 lying practically motionless for several 

 minutes. If a strong light is moved about 

 near them they come out of their feint 

 much more quickly than when left entirely 

 alone, and soon begin to follow the light 

 with much vigor. The first responses, how- 

 ever, are slight and consist of a small lat- 

 eral movement of the head when the light 

 is moved from side to side. Shortly after 

 this the animal will respond by vertical 

 head movements as the light is moved back 

 ajid forth over the long axis of the body. 



Moving the light around in a circle, the 

 head responds by circular movements of a 

 most regular and precise kind. For every 

 position of the light there is a correspond- 

 ing attitude of the head. Next following 

 the head reflexes come the reflex move- 

 ments of the respiratory tube, which be- 

 comes raised and lowered coincident with 

 the head as the light is moved to and fro 

 above the body. After a greater or less 

 interval the animal rises on its legs, and if 

 the light is now moved from side to side, 

 the body will perform swaying movements, 

 leaning over strongly towards the side on 

 which the light is held. The legs on the 

 side towards the light are strongly flexed, 

 while those on the opposite side are held 

 in a state of extension. If the light is 

 passed to and fro in a longitudinal direc- 

 tion corresponding swaying movements are 

 likewise performed. "When the light is in 

 front, the animal bows down; when it is 

 moved behind, the anterior end of the body 

 is elevated, often at an angle of forty-five 

 degrees. Moving the light around the ani- 

 mal in a circle, the body follows with cor- 

 responding motions. These responses are 

 so regular and definite that one might al- 

 most tell what particular attitude of the 

 body, legs and head will be assumed for a 

 given position of the light. Light in Ban- 

 atra apparently produces a powerful effect 

 upon the tension of the muscles and may 

 be made to control the behavior of the 

 creature in a most precise and arbitrary 

 manner. 



* Studies on Protoplasmic Structure: A. 



W. Greeley, Washington University, St. 



Louis. 



The influence of chemical, electrical, 

 thermal and osmotic stimuli upon the pro- 

 toplasmic structure. The effect of these 

 variations in structure upon the element- 

 ary vital phenomena, with special refer- 



