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THE AMEBIC AN NATURALIST [Vol. XLII 



female, was divided into equal parts. These parts were 

 then fertilized by milt from a single male at tempera- 

 tures differing from each other by 5°, 10°, 15° or 20° C. 

 After a few minutes the two parts were again brought 

 under identical conditions and so kept until hatching. 

 At the expiration of a certain period, when practically 

 all of the living embryos had hatched, all were fixed by 

 the aceto-sublimate-formalin method, which was found 

 to leave them well straightened. Careful records of 

 mortality, rate of hatching, etc., in the different lots were 

 kept. Measurements to be made upon the embryos, with 

 a view to determining the tangible effects of such differ- 

 ences in treatment, are not yet complete. (2) A study of 

 the alleged interference in branchial circulation result- 

 ing from the transfer of fishes from salt to fresh water, 

 and vice versa, was also taken up. The conclusion of Bert 

 and Mosso that such interference occurs in consequence 

 of a clogging of the branchial capillaries by distorted 

 blood corpuscles, was thought to be worth testing in view 

 of recently published work by the director of the labora- 

 tory upon some other effects of changes in salinity. The 

 common smooth dog-fish {Mustelus canis), the scup 

 (Stenotomns chrysops) and the killifish (Fnndulus 

 heteroclitus) were experimented upon, the first two named 

 being species which succumb quickly when transferred to 

 fresh water, while the last named is commonly able to 

 survive for some days in fresh water. The hypothetical . 

 clogging of the branchial vessels in these species was 

 tested by passing physiological salt solution through the 

 conus arteriosus at definite pressures, and the gills were 

 then fixed for microscopical examination. Results im- 

 mediately apparent revealed no such contrast as the state- 

 ments of both Bert and Mosso would lead one to expect 

 between fishes taken directly from salt water and those 

 dying in fresh water. Further work will be necessary 

 before a more definite statement of the results can be 

 made. 



