Septembeb 7, 1906.] 



SCIENCE. 



293 



section held a joint meeting with. Section 

 A, in which the teaching of mechanics by 

 experiment was discussed. 



As usual at these association meetings 

 there were some evening lectures on more 

 general topics. A most interesting lec- 

 ture on Volcanoes was given by Mr. 

 Tempest Anderson, of York; another was 

 on the manufacture of light, by Professor 

 Sylvanus Thompson, and another on The 

 Electrical Signs of Life and their Aboli- 

 tion by Chloroform, by Dr. A. W. Waller. 



In 1907 the association meeting will be 

 held in Leicester ; in 1908, in Dublin ; and 

 in 1909 in Winnipeg, Canada. 



Gary N. Calkins. 



THE AMERICAN ASSOCIATION FOB TEE 



ADVANCEMENT OF SCIENCE. 



SECTION F— ZOOLOGY. 



Section F at the Ithaca meeting held 

 joint sessions for the reading of papers 

 with the American Microscopical Society, 

 June 29 and 30. The following papers 

 were read under the auspices of Section F. 



Chromosome Relations in the Sperma- 

 tocytes of Oniscus: M. Louise Nichols, 

 University of Pennsylvania. 

 In the equatorial plate of the first ma- 

 turation division, chromosomes differing 

 from each other in shape may be discov- 

 ered. They are of three kinds: First, 

 straight or dumb-bell-shaped, in which the 

 halves of the bivalent chromosome lie end 

 to end; second, curved or crescent-shaped, 

 in which the halves lie end to end but with 

 the extremities curved toward each other; 

 third, a form in which the halves lie side 

 by side. In each type a split may be seen 

 running the length of the individual 

 chromosome and the first division is redue- 

 tional. In the prophases of the first ma- 

 turation division chromosomes of the first 

 and second types are present as straight or 

 curved rods; the third type is represented 



frequently by rings, complete or nearly so, 

 occasionally by V-shaped structures. The 

 reduced number of chromosomes, as far as 

 could be determined, is sixteen. Of this 

 number, two have the ring form in the 

 prophase, two the crescent form, while 

 the remainder are straight or dumb-bell 

 shaped. The chromosomes vary somewhat 

 in size, but the differences are not stri- 

 kingly great. The largest have the ring 

 form, the smallest are straight. A tend- 

 ency to localization in the nucleus is ob- 

 servable. The ring forms usually lie on 

 opposite sides of the nucleus, separated by 

 a crescent. Similarly the crescent forms 

 lie on opposite sides with a ring between. 

 Notes on the Poison Organs in Fishes: 



H. D. Reed, Cornell University. 



Axillary poison glands are found in aU 

 species of Noturus and Schilheodes. In 

 S. gyrinus and S. nocturnus poison glands 

 are found enveloping the pectoral and 

 dorsal spines. Wherever found these 

 glands are invaginations of the skin, in 

 which respect, as well as in structure, they 

 are identical with the poison organs of the 

 weever fishes. 



Exhibition of Bird Draivings: L. A. 

 FuEETES, Ithaca, N. Y, 



ExhiMtion of and Remarks upon Certain 

 Rare or Unique Specimens in the Cornell 

 University Museum of Neurology and 

 Vertebrate Zoology: Burt G, Wilder, 

 Cornell University, 



Among the specimens are the smallest 

 recorded manatee fetus; a human embryo 

 about 4 mm, long attached to the vitellus; 

 an embryo shark with undivided cerebrum ; 

 the brain of the anguin, or frilled shark, 

 presenting the indifferent relation of the 

 cerebral and olfactory portions more nearly 

 than in any other known vertebrate; the 

 brain of Ceratodus, presenting the char- 

 acteristic dipnoan ventral cerebral exten- 

 sions; the brains of Tarsius, Cheiromys 



