164 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



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 larvae. 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 year (1900) from the beginning of May to the 

 middle of July. 



Report on the Shrimp Trawling Statistics Collected 



by Mr. G. Eccles on the Mersey Shrimping 



Ground during the period 1893 — 1899. 



By Jas. Johnstone, B.Sc, and J. T. Jenkins, 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. 



