MARINE BIOLOGICAL STATION AT PORT ERIN. 31 



killed and the gonads extracted iu the fresh condition, 

 others were kept fed in the tanks and the gonads 

 extracted, and still others were kept for a period without 

 food and then killed and the gonads extracted. 



" So much can already be said that, so far from 

 representing an exhausted gland at this time of year, 

 the gonads in both sexes are as large as in the breeding 

 season and contain both fats and glycogen in large 

 amounts. The glycogen content is being investigated 

 by Mr. Coppin, while Mr. Adams is determining the 

 nature and amount of the fats. 



" One important point to be determined is whether 

 the amount of metabolic material stored up varies with 

 the state of nutrition, and whether such variations occur 

 apart from the breeding season." 



Mr. W. Eiddell, M.A., was at work at Port Erin 

 during both the Easter and the summer vacations, 

 assisting me with the Plankton investigation ; but in the 

 intervals of that work lie took up one or two other 

 matters. He continued his systematic work on the 

 Polychaeta of the neighbourhood, and to the list given in 

 last report he has been able to add Nereis virens, Glycera 

 siphonostoma and Notophyllum foliosum, the latter 

 dredged off Dalby in September, 1911. Mr. E-iddell 

 also commenced an investigation into the nature of the 

 disease which has been causing much damage to the 

 plaice in the spawning pond during the last few years, 

 but this work has hardly been carried far enough as yet 

 [q warrant any definite statement. 



Dr. W. J. Dakin reports to me as follows on his 

 research work : — 



" During the Easter vacation I continued some of 

 the osmotic pressure experiments commenced at 

 Helgoland. These experiments had shown that the 



