ON DEVELOPMENT OF EARLY STAGES OF UROSALPINX CINEREA (SAY) AT CONSTANT TEMPERATURES AND THEIR TOLERANCE TO LOW TEMPERATURES

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Abstract
1. The rate of ova development increases directly with the increase in temperature from 15.0° to 25.0° C. No increase in the rate of ova development was observed above 25.0° C. 2. Optimum temperature for ova development of U. cinerea of Long Island Sound appears to be 20.0° C., or between 20.0° and 25.0° C. 3. Egg cases of U. cinerea kept in sea water can withstand sub-freezing temperatures for longer periods than egg cases exposed to sub-freezing air temperatures. 4. In sub-freezing temperatures, the percentage mortality increases with the period of exposure and with a decrease in temperature. 5. Egg cases kept at 10.0° C. for as long as 84 days showed partial development and were capable of producing normal protoconchs when returned to 20.0° C.; whereas, egg cases kept at 7.5° C. for 54 days were not viable. 6. Our experiments and observations suggest that egg cases remaining through the winter in Long Island Sound will not contain viable ova in the spring.

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