ZOOPLANKTON 271 



EUPHAUSIACEA 



Boden (1955) notes that fourteen species of euphausiids were represented in the collection from survey I. 

 The numbers of adult euphausiids were quite small, but larvae of some species were numerous in some 

 of the catches. 



Nyctiphanes capensis Hansen was only taken at the stations on the continental shelf — excepting one 

 larva which occurred in the 1000-750 m. haul at WS 997. It was present on all three latitudinal lines 

 of stations. On the Orange river line the larvae extended farther seawards than the adults, but on the 

 Walvis Bay line the greatest abundance of larvae— totalling 5000 specimens — occurred at WS 979, 

 and this coincided with the greatest number of adults (twenty-seven) on this line. 



The adults of Euphausia lucens Hansen, an oceanic species, occurred in very small numbers at the 

 offshore stations, but a large haul of 237 adult females was taken in the 50-0 m. layer at WS 1000 on 

 the continental shelf, and the adults were also present off the Orange river mouth (WS 1001 and 

 WS 1002). The larvae were mainly abundant at the offshore station on the Orange river line (WS 996), 

 but Barry (1956) in comparing Boden's material with some from New Zealand, questions the identifica- 

 tion of these larvae as E. lucens and considers they may belong to some other species. 



E. tenera Hansen, a tropical to subtropical form, occurred only at WS 996, at the offshore end of the 

 Orange river line. Most larvae of this species were in the 250-100 m. haul. Boden is of the opinion 

 that many of the unidentified pre-furcilia larvae encountered at other stations may in fact be E. tenera. 



E. recurva Hansen, which occurred offshore on the Walvis Bay and Orange river lines, shows some 

 suggestion of diurnal migration. E. hanseni Zimmer was represented by four adults in the 250-100 m. 

 layer at stations WS 978 and 987 just off the continental shelf. 



Of Nematoscelis megalops G. O. Sars mostly larvae were taken at the oceanic stations, and these, 

 concentrated at about 250 m. during the day, show a diurnal vertical migration. 



A species usually common in this area, Thysanoessa gregaria G. O. Sars, was present in very small 

 numbers, well offshore. 



Four species of Stylocheiron were also recorded. 



Decapoda and Stomatopoda 

 The collections of survey I have been examined and described by Dr M. V. Lebour (1954). Nearly- 

 all of the material consists of larval stages, but a few species are represented in adult form. A large 

 number of genera and species were represented, but few were present in any abundance and the small 

 number of individuals does not warrant a detailed account of their distribution. 



Calliatiassa larvae were present at the inshore stations at Walvis Bay and on the continental shelf 

 on the Orange river line. The phyllosoma larvae of jfasus lalandii (Lamark), the common crawfish of 

 South Africa, were represented only by two specimens taken at stations WS 992 and 1000. 



Among the Brachyuran larvae, a species of Ebalia occurred at both the offshore and shelf stations 

 on the Orange river line. 



Five adult specimens of the stomatopod, Squilla armata Milne-Edwards, were taken in a trawl in 

 128 m. of water at WS 990. Larvae of the same species occurred in ones or twos at the three inshore 

 stations off Orange river mouth. 



MOLLUSCA 



The collections of planktonic molluscs have been reported on by Dr J. E. Morton (1954). 



Specimens of the surface-living gastropod, Ianthina ianthina (Linnaeus) and /. globosa Swainson 

 were taken by hand nets at two offshore stations (WS 1057 and 1058) on survey II. The heteropod, 



TT^ 



WOODS 

 HOLE. 

 MASS. 



