of the catch by volume. Siphonophores were found only from October to mid-April 

 and never appeared in large numbers. A few very small sea-anemones occurred 

 in catches made on four occasions, June 3 and October 16, 1954; November 3, 

 1955; and December 12, 1957. 



CTENOPHORA 



Comb Jellies 



Comb jellies of the order Beroida commonly occurred in the plankton catches 

 in moderate abundance except during the months of July, August, and September 

 when very few were observed. They were present in exceptionally large numbers 

 on June 26, 1958. 



ASCHELMINTHES 



Rotifers 



Rotifers were observed on three occasions, April 14 and May 19, 1954; and 

 June 24, 1955, and then only in relatively small numbers (25-60 per sample) » 

 Attempts to hold them in aquaria were unsuccessful, all disappearing overnight. 



CHAETOGNATHA 



Arrow Worms 



Arrow worms, or sagitta, were of common occurrence. Their relative 

 abundance throughout the period is presented in figure 7. On three occasions 

 they were exceptionally abundant, namely: March 31 and May 11, 1955; and 

 November 28, 1956. They were least abundant throughout the summer and early 

 fall (June through October). 



CATEGORIES OF ABUNDANCE 



NONE 



500 1500 10,000 + 

 1500 10,000 



JAN 

 (41) 



Figure 7.-- Percentage occurence of arrow works in 

 categories of abundance (Nov. 1953 - May 1958). 



21 



