560 L. R. CRAWSHAY. 



food was added. Apart from one exceptional example in which a speci- 

 men, infected with the parasite Microniscus, lived for 40 days, the 

 maximum was no higher than 23 days, which was 4 days in excess of the 

 next highest period. 



In l-litre flasks, 5 experiments in " outside '" water, containing from 

 3 to 5 specimens (September 27th to October 23rd) showed a higher 

 average, of about 22 days, than was obtained in the finger-bowls, and 

 a much higher maximum of 84 days. In the experiment in which this 

 high maximum occurred (October 21st) the shortest life period was 

 23 days, and the average for the three individuals was about 44 days. 

 No clear explanation was found for the fact that in three other Calanus 

 experiments, started two days later under almost identically similar con- 

 ditions, the maximum was no higher than 27 days, and the average 

 about 16 days. 



Temora longicornis. In finger-bowls, 9 experiments with from 6 to 

 12 specimens (June 19th to August 8th) were far less successful than 

 in the case of Calanus, and a maximum of 23 days, which was obtained 

 in one case in Berkefeld water, was far in excess of the life period 

 that was usually sustained. The data for averages are incomplete, but 

 with the exception mentioned the longest life did not exceed 11 

 days, and the average for all the experiments was probably not above 

 5 days. 



In 1-litre flasks, 2 experiments, with 7 and 10 specimens, in sterihsed 

 " outside " water (September 18th and 27th), were little more successful 

 than those in the finger-bowls, the maximum being about 17 days, and 

 the average life probably not exceeding 5 or 6 days. In connection 

 with the mortality of this species, it is very remarkable that in the first 

 of these two experiments, 6 Acartia which were included in the same vessel 

 at the same time subsequently reached the high average of about 60 

 days. 



In 11-litre bell-jars (Position B), an experiment with 70 specimens, 

 in Berkefeld water (July 17th) failed completely, all dying within two days. 

 Of a similar number, placed in the same bell- jar with the same water 

 (July 19th), none lived for more than about a fortnight. In an experi- 

 ment with 50 specimens in " outside " water (July 17th), a few only 

 survived the first fortnight, though a single specimen lived for 48 days. 

 Mention has already been made (p. 557) of the irregular and high 

 temperatures that were recorded for the water in bell- jars in this position 

 at this period, showing over four successive days a range of nearly 9°, 

 with a maximum daily variation of 5°, and these irregularities were 



