SEA-FISHERIES LABORATORY. 417 



January 3rd, and were present every month till 

 October 10th. In 1911 the eggs occnrred from 

 January 9th to September 10th. They disappeared after 

 that date, but were again present on December 29th. 

 Although rockling eggs were obtained on December 29th, 

 1911, they were not observed in 1912 earlier than 

 January 26th. After that date they occurred throughout 

 each month till September 7th. The only month in the 

 whole period of the six years' investigation in which no 

 rockling eggs were observed was November. 



Young rockling or mackerel midges from 10 to 

 20 mm. in length are frequently captured in the surface 

 nets in various parts of the Irish Sea between the 

 beginning of July and the end of August. 



Ctenolabrus rwpestris, Linn. — Jago's Goldsinny. 



A very small egg (0'8 mm. to 0'9 mm.) with 

 transparent yolk and no oil globule has been identified 

 as belonging to Jago's goldsinny. It generally occurs 

 in the plankton of the area in small numbers between the 

 beginning of June and the end of September. In 1907 

 the eggs were found in the collections taken between 

 August 13th and the end of September. It is the only 

 year during the period of intensive investigations in 

 which the records show it to have been not uncommon. 

 It was only observed on June 6th and August 6th in 

 1908. No records at all were obtained for 1909. It was 

 present in the surface collections taken on August 10th 

 and 12th in 1910, but apparently not at any other time. 

 1911 was also a blank year, and not a single specimen of 

 the egg was obtained. It occurred once in 1912 in a 

 surface collection taken on August 9th. 





