BY 
they were leaving the parent and put into water direct 
from the sea that had been carefully filtered through fine 
filter paper. These eggs always developed into free 
swimming larve. Fertilisation therefore probably took 
place in the branchial chamber of the parent.* It was 
also observed that practically the whole of the reproduc- 
tive elements were discharged at one emission extending 
from one to three hours. The same mussel did not again 
set free any more reproductive elements. When such a 
spent mussel was opened up and examined the whole 
reproductive organ was found to have collapsed. 
The mussels on the beds, by the time those in the tanks 
had ceased to emit reproductive elements and had become 
quite thin, also took on the same appearance. From the 
observations carried on at Piel the conclusion has been 
arrived at that the spawning period of the mussels in the 
northern part of our district may be set down as having 
lasted this vear (1900) from the beginning of May to the 
middle of July. 
Report on THE Surimp TRAWLING Statistics CoLLECTED 
BY Mr. G. Eccites on THE MERSEY SHRIMPING 
(FROUND DURING THE PERIOD 1893—1899. 
By Jas. Jounstone, B.Sc., and J. T. Jenxins, D.Sc. 
In 1893 the Committee began a series of observations, 
on the lines indicated in a scheme drawn up by Professor 
* Professor M’Intosh some years ago investigated various points in the 
reproduction of the mussel. Amongst other things, he determined that 
the sperms were capable of living for twenty-four hours after being 
removed from the parent. This has been confirmed by the work at Piel, 
but the intervals between the obvious shedding of sperms and eggs in the 
tanks were much longer than twenty-four hours, and during these periods 
the sperms, even if alive, would be carried away in the waste water, 
