January 27, 1911] 



SCIENCE 



157 



SOCIETIES AND ACADEMIES 



THE NEW YOBK ACADEMY OF SCIENCES 

 SECTION OF BIOLOGY 



A REGULAE meeting of the section of biology was 

 held at the American Museum of Natural His- 

 tory, November 14, 1910. In the absence of 

 Chairman Charles B. Davenport, Dr. Alexander 

 Petrunkevitch presided. The following papers 

 were read: 

 The Effects of Exposure on the GUI Filaments 



of Eishes: Raymond C. Osbubn. 



Salmonoid fishes hatched and reared under arti- 

 ficial conditions frequently show a malformation 

 of one or both of the gill covers, as a result of 

 which the gill filaments are exposed. This condi- 

 tion has been observed in many hatcheries, the 

 percentages sometimes 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 follow- 

 ing 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 ex- 

 posed filaments are found to be quite abnormal. 

 The epithelium, instead of being composed of thin 

 flattened cells, is greatly thickened, consisting of 

 cuboid or columnar cells, and in some cases sev- 

 eral layers of the cells are found. The secondary 

 laminae, in which respiration for the most part 

 takes place, are often reduced or wanting and the 

 blood capillaries are not fully developed. 



The hypertrophy of the epithelium, while it 

 undoubtedly protects the filaments against abra- 

 sion, must at the same time seriously interfere 

 with their function in respiration. The cause of 

 the deformity of the opercle is unknown. Fish 

 culturists have noted its appearance very early in 

 fry, but whether it is congenital or is induced by 

 crowding or by other untoward conditions in the 

 hatching trays, further observations must decide. 

 Courtship in Tarantulas: Alexander Peteunke- 



VITCH. 



The instincts of the male tarantula change 

 suddenly at the period of maturity. From a 

 creature with domestic habits he develops into a 

 vagabond. Disregarding personal danger he con- 

 structs a sperm-web into which he throws out 

 his sperm and pumps it then into both of his 

 palpi. Tn the search for the female he is entirely 

 dependent upon h's sense of touch, his sense of 

 sight l^eing entirely inadequate for the purpose. 

 The courtship is therefore very short and consists 

 in lea ing the female wi h 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. 



At the regular meeting of this section held at 

 the American Museum, December 12, 1910, Mr. 

 Roy W. Miner presiding, the following papers 

 were read: 

 The Effect of Changes in Water Density on the 



Blood of Fishes: G. G. Scott. 



When salt water fishes are placed in fresh 

 water they gain in weight. Investigation of the 

 blood shows that there is a decrease in number 

 of corpuscles per cubic millimeter and that the 

 specific gravity of the blood decreases. 



Tests with the Beekmann apparatus show that 

 the freezing point of the blood of such fishes is 

 higher than that of normal blood. If the fishes 

 are placed in a solution of sea water plus sea 

 salt, the corpuscle count is increased, the specific 

 gravity of the blood is greater and the freezing 

 point of the blood is depressed. A chemical exam- 

 ination of the chlorides of the blood of normal 

 fish as compared with the chlorides of fishes kept 

 in fresh water, shows that the loss of chlorides in 

 case of the fishes experimented on is greater than 

 the mere dilution of the blood by the endosmosis 

 of water would account for. Hence, under the 

 abnormal conditions to which the fish is subjected 

 the gills become permeable to salts. The osmotic 

 pressure of the blood is thus profoundly changed. 

 That these changes reach the tissues is indicated 

 by investigations now going on. The death of the 

 fish which usually accompanies such sudden 

 transitions as are employed in these experiments 

 is possibly caused by conditions set up similar ta 

 those in such diseases as dropsy. It is hoped that 

 further investigations now being carried on will 

 clear up this question. 

 Marine Ecology and its Representation in a 



Museum: Roy W. Miner. 



The speaker described the chief associations of 

 marine animals to be found between the tides or 

 just below the lower tide limits along the north 

 Atlantic coast, with especial reference to the 

 annulates and molluscs and the fauna of wharf 

 piles in the Woods Hole region and the north 

 shore of Long Island. The methods of collecting 

 were then briefly outlined, and the chief steps for 

 preserving data, observations, etc., for museum 

 ecological groups were mentioned. The speaker 

 then discussed the problems connected with con- 



