the sea urchin Dladema antillarum , retreating between the spines if 

 approached. 



Macrurans consisted mostly of penaeids, roughly one third belonging to 

 the genus Lucifer . Macrurans as well as chaetognaths, thaliaceans, 

 brachyuran and anomuran zoea, and cyclopoid copepods were caught 

 mostly during the first few days, possibly in relation to the lunar 

 phases, as was true for bipinnaria larvae, which appeared only on the 

 16 and 17, October at night, primarily at station III. 



Polychaetes were relatively rare in the samples but were attracted in 

 large numbers to hand lamps held near the sandy bottom. Phyllosoma 

 larvae were collected only at the lights. Large specimens of over 

 20 mm length were observed at the beginning of the mission, but the 

 samples taken later on contained only smaller specimens up to 7 mm 

 in length. 



Gnathiids were found mostly at night, but away from the lights, 

 mainly at station IV. The isopods found at stations II and IV were 

 nearly all Portunion , Epicaridea, which are parasitic on copepods. 

 At night, there was invariably a much greater number of individuals 

 present, also many more species were represented. The biomass 

 collected ranged in the order of a few milligrams in the daytime to 

 several hundred milligrams per cubic meter at night. 



The following characteristics were noted in the distribution of 

 planktonic animals in relation to the substrate: 



Station I - Most of the ostracods, harpacticoids, larvaceans, fish 

 larvae, many macrurans; few cyclopoid copepods; generally few species 

 represented. 



Station II - Some larvacea, thaliacea, brachyuran megalopa; generally 

 many species but with a moderate to low frequency of occurrence. 



Station III - Relatively many macrurans, brachyuran zoea, cyclopoids, 

 bipinnaria larvae, but very few chaetognaths. The greatest species 

 diversity was found at this station; the plankton contained the most 

 open water forms . 



Station IV - Mysids and chaetognaths very frequent; ostracods and 

 cyclopoids relatively frequent. Macrurans were uncommon, as were 

 calanoids except for a few cases of schooling. 



Station V - Chaetognaths and thaliacea frequent; macrurans and fish 

 larvae relatively rare. Calanoids frequent at night; the greatest 

 number of organisms were taken at this station at night. The 



VI-283 



