GRAPSIDAE 



This family is represented by one species, Sesarma reticulatum Say, which was 

 found in close association with fiddler crabs along the lagoon shores but in much 

 less abundance. 



STOMATOPODA 



SQUILLIDAE Mantis Shrimp 



Larvae of mantis shrimp, varying in number from 1 to 20 specimens, occa- 

 sionally appeared in the plankton catches, chiefly in the warmer months. 



MOLLUSCA 



PELECYPODA Bivalve Mollusks 



Tiny bivalves, approximately 1.5 mm. in diameter, were present in only 

 10 of the plankton collections over the entire period. Several thousand appeared 

 in the catch made on November 18, 1955, but the average number observed was 

 between 50 and 100 specimens. More than 90 percent of the pelecypods were taken 

 in the months of April, May, October, and November. 



GASTROPODA Snails 



Veligers, and gastropods with recently formed shells (1-3 mm. in diameter), 

 occurred in small numbers (usually less than 50) in about 5 percent of the plankton 

 catches. All were taken in the months April through October. 



Periwinkles (Littorinidae) and dog whelks (Thaisidae) were very abundant 

 on the rocks around the basin. On one occasion, over 600 specimens of the latter 

 were collected in less than an hour. 



A small nudibranch of sea slug, approximately 1 cn^. in length, was found in 

 the collection made January 28, 1955, and is our only record of this order. 



CEPHALOPODA 



LOLIGINIDAE Squids 



Juvenile squid, 4 to 15 nnm. in length, occurred sporadically in the plankton 

 catches, one in June and one in December 1954; one in March 1955; nine in April 

 and eight in October 1956. Thirty-three young squid, 3 to 6.5 cm. in length, were 

 taken in the series of beach-seine hauls made in area "A" in November 1955. 



ECHINODERMA 



Echinoderm larvae are another example of planktonic forms that appeared 

 sporadically in the collections and in very small numbers. A few specimens were 

 observed on six occasions, all in the warmer months. 



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