306 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



venial maxima, and at a time of year when several of the 

 most important groups of organisms in the sea are on the 



wane. 



We can obtain some information in regard to the 

 distribution of Sagitta throughout the year in other parts 

 of the British seas from the records of E. T. Browne* in 

 the Clyde, Gamblet at Valencia, and Gought at 

 Plymouth. If we arrange the essential facts in columns 

 opposite the months we get the table shown on page 305. 



The Plymouth record seems to show that large 

 quantities are seldom obtained except in October, and that 

 the minimum is in March. At Valencia there are shoals 

 in October-November, and a scarcity in spring. In the 

 Clyde there is an increase in October-November, and 

 again a scarcity in spring, in August and in December, 

 and the organism is fairly common in July. 



Returning now to the Port Erin column, we find it 

 agrees with all the others in showing a scarcity in early 

 spring; has a marked maximum in June-July which has 

 not been noticed elsewhere ; and has a second but smaller 

 increase in October-November which seems indicated at 

 the other localities also. 



In the Baltic, according to Lohmann, Sagitta is 

 most abundant in September and onwards through the 

 winter — under possibly rather different conditions of 

 temperature and salinity from those of the Irish Sea. 



Oiko PLEURA. 



The common Oikoplcuva dioica is present in our 

 collections throughout the year, and is well represented in 

 every month. There is a marked winter minimum in 



* Proc. Boy. 8oc. Edin., Vol. XXV. p. 77'.). 1905. 



1 Ttoyal Irish Acad. Proc. Series III. Vol. V, p. 745. 1900. 



♦ North Sea Investigation*, Blur-Looks Cd 2670, 1905. and C.I. 3837. 

 1907. 



