REC0RD8 OF MEETINGS 437 



Summary of Papers. 



Dr. Osburn said in abstract : Salmonoid fishes hatched and reared 

 under artificial conditions frequently show a malformation of one or both 

 of the gill covers, as a result of which the gill filaments are exposed. This 

 condition has been observed in many hatcheries, the percentages some- 

 times being as high as twenty per cent. The deformity in the fishes 

 studied is produced by the rolling in of the operculum. 486 yearling 

 silver salmon reared in the New York Aquarium were examined with the 

 following results: Normal, 397; right opercle short, 44; left opercle 

 short, 27 ; both opercles short, 18 ; percentage of abnormality, 18.31. On 

 examination under the microscope, the exposed filaments are found to be 

 quite abnormal. The epithelium, instead of being composed of thin flat- 

 tened cells, is greatly thickened, consisting of cuboid or columnar cells, 

 and in some cases several layers of the cells are found. The secondary- 

 laminae, in which respiration for the most part takes place, are often re- 

 duced or wanting, and the blood capillaries are not fully developed. The 

 hypertrophy of the epithelium, while it undoubtedly protects the fila- 

 ments against abrasion, must at the same time seriously interfere with 

 their fimction in respiration. The cause of the deformity of the opercle 

 is unknown. Pish culturists have noted its appearance very early in fry, 

 but whether it is congenital or is induced by crowding or by other un- 

 toward conditions in the hatching trays, further observations must decide. 



Dr. Petrunkevitch said in abstract: The instincts of the male taran- 

 tulas change suddenly at the period of maturity. From a creature with 

 domestic habits, he develops into a vagabond. Disregarding personal 

 danger, he constructs a spermweb into which he throws out his sperm and 

 pumps it then into both of his palpi. In the search for the female, he is 

 entirely dependent upon his sense of touch, his sense of sight being en- 

 tirely inadequate for the purpose. The courtship is therefore very short 

 and consists in beating the female with his front legs. The danger of 

 being hit by the fangs of the excited female is prevented by catching 

 them with the hooks on the front legs. The coitus lasts not longer than 

 one-half minute, after which the spiders cautiously separate. A few 

 weeks later the males die, apparently a natural death. 



Professor Charles B. Davenport, Chairman of the Section, was renomi- 

 nated for the Chairmanship for 1911. 



Dr. L. Hussakof, Secretary of the Section, was renominated and re- 

 elected for 1911. 



The meeting then adjourned. 



L. Hussakof, 



Secretary. 



