476 



SCIENCE 



[N. S. Vol. XLI. No. 1056 



animals from their enemies, a series of about 140 

 experiments, covering a period of six years, has 

 been carried out with various species of caged, 

 and in a few cases with wild birds, to which were 

 fed several kinds of small mammals and insects. 

 The latter were placed upon different backgrounds, 

 with some of which they formed strong contrasts, 

 while others they closely resembled. The birds 

 were then allowed to choose between that prey 

 which resembled, and that which contrasted with 

 its background. 



The experiments may be divided into two classes 

 — those in which the birds usually approached 

 their prey swiftly from a short distance, and those 

 in which they approached it slowly, and seized it 

 only after careful inspection. In the former class 

 over 90 per cent, of the combinations chosen were 

 ■ contrasting, while in the latter, the contrasting 

 combinations were chosen but little oftener than 

 the non-contrasting ones. 



The experiments indicate that the color of a 

 motionless animal has a decided survival value when 

 it is attacked by birds which approach it swiftly 

 from a distance of even a few feet. 



Immunity of Fowls to Cysticerci of Certain Ces- 

 todes: J. E. Ackert 



Eegeneration of Head Parts in Earthworms After 

 Eemoval of the Anterior Portion of the Diges- 

 tive Tube: H. R. Hunt. (Introduced by Her- 

 bert W. Eand.) 



The object of these experiments was to deter- 

 mine whether the brain and commissures could be 

 regenerated and the stomodeum formed in regen- 

 erating earthworms in the absence of the anterior 

 end of the digestive tube. The first three anterior 

 segments of the worms were removed and the di- 

 gestive tube carefully removed from the first five 

 or six segments posterior to the point where the 

 head was cut off. One hundred and seventy- 

 seven individuals of Eisenia fcetida and thirty- 

 two individuals of Helodrila-s calliginosus were 

 used. Seventy-eight worms survived. In six 

 specimens head parts regenerated when the an- 

 terior end of the digestive tube was three to five 

 segment lengths from the anterior end of the worm. 

 The six worms fall into three classes: in the first 

 class a stomodeum was formed; in the second 

 class a brain fundament and commissures were re- 

 generated; in the third class a brain fundament 

 and commissures regenerated and a stomodeum 

 was formed. 



I am indebted to Professor H. W. Eand, of Har- 

 vard University, for many helpful suggestions. 



An Interesting Snail from Minnesota and a Prob- 

 lem in Geographical Distribution: E. W. H. 



WOLCOTT. 



Exhibits 

 During the meeting the following exhibits were 

 made in one of the rooms of the Zoological Lab- 

 oratory of the University of Pennsylvania: 



Exhibits and Demonstrations 



Franklin D. Barker: The Absence of Male 

 Eeproductive Organs in Trematodes. 



J. W. Mavor: The Larval and Post-larval De- 

 velopment of the Coral, Agaricia Fragilis, Dana. 



Chester H. Heuser: Drawings and Models of 

 the Stomachs of Embryo Cat, Albino Eat, Pig 

 and Sheep. 



E. J. Werber: Demonstrations of Some Sectioned 

 and Unsectioned Material of Monstrous Embryos 

 of Pundulus. 



Harold S. Colton: Methods Used in Producing 

 Changes "Within Pure Lines of the Pond Snail, 

 Lymncea. (Eoom 104, Zoological Laboratory.) 



T. H. Morgan, A. H. Sturtevant, C. B. Bridges 

 and H. Muller: Demonstration of the Pour Hered- 

 itary Groups and the Eour Pairs of Chromosomes 

 of Drosophila. 



S. O. Mast: Autochromes from Life Showing 

 Adaptation in Color in Plounders. 



Caswell Gbave, 

 Secretary-treasurer, American Society 

 of Zoologists 



SOCIETIES AND ACADEMIES 



THE AMERICAN MATHEMATICAL SOCIETY 



The one hundred and seventy-fifth regular 

 meeting of the society was held at Columbia Uni- 

 versity on Saturday, February 27, 1915, with an 

 attendance of 39 members at the two sessions. 

 President E. W. Brown occupied the chair, being 

 relieved by Vice-president Oswald Veblen at the 

 afternoon session. The following persons were 

 elected to membership : Professor J, V. Balch, 

 Bethany College; Professor E. J. Berg, Union 

 College; Mr. Millar Brainard, Chicago, 111.; Mr. 

 L. C. Cox, Purdue University; Mr. C. H. Forsyth, 

 University of Michigan; Dr. H. C. Grossard, Uni- 

 versity of Oklahoma; Mr. M. 8. Knebelman, Le- 

 high University; Dr. W. V. Lovitt, Purdue Uni- 

 versity; Dr. L. C. Mathewson, Dartmouth College; 

 Mr. A. L. Miller, University of Michigan; Dr. 

 Bessie I. Miller, Johns Hopkins University; Mr. 

 I. E. Pounder, University of Toronto; Mr. L. L. 

 Steimley, Indiana University; Mr. Chid-Cheow 



