THE PLANKTONIC DECAPOD CRUSTACEA AND 

 STOMATOPODA OF THE BENGUELA CURRENT 



PART I. FIRST SURVEY, R.R.S. 'WILLIAM SCORESBY', 



MARCH 1950 



By Marie V. Lebour, D.Sc. 



(Text-figs. 1-6) 



INTRODUCTION 



THE R.R.S. 'William Scoresby' made two surveys in 1950 of the Benguela Current off the coast of 

 South-West Africa. The plankton hauls so obtained were sorted by Dr T. J. Hart, who handed 

 the Decapoda and Stomatopoda over to me. The material from the first survey (March, Stations 

 WS 977-1002) forms the basis of this report. The second survey will be dealt with subsequently. 



The adult specimens consisted of two species of Gennadas and one of Pasiphaea. The rest were all 

 larvae. One of the commonest of these was a species of Callianassa which occurred in several hauls, 

 and the most frequent crab larva was a species of Ebalia, closely related to E. tuberosa. A pagurid larva 

 was of special interest as it represents a type hitherto undescribed. It is here compared with one from 

 Bermuda, very closely related and so far unknown. 



The Stomatopod larvae all belong to one species and are almost certainly Squilla armata which is 

 the commonest form in these regions. 



ACKNOWLEDGEMENTS 



My best thanks are due to Mr F. S. Russell, Director of the Marine Laboratory for allowing me to 



work at Plymouth. 



SYSTEMATIC 



Penaeidea 



Penaeidae 



_ L . ,~ , . Aristeinae 



Gennadas guchristi (Caiman) 



Caiman, 1925, p. 6. 



Balss, 1927, p. 261 (as Amalopenaeus). 



Occurrence. St. WS 997, 1 000-0 m. 



Distribution. Known from near the Cape of Good Hope and in the East Atlantic. 



Gennadas similis Stephensen 



Stephensen, 1923, p. 12. 



Balss, 1927, p. 256 (as Amalopenaeus). 



Occurrence. St. WS 996, 1000-750 m. 



Distribution. South-east and East Atlantic. The original locality is the Bay of Cadiz (Stephensen). 



Gennadas sp., 1 protozoea 

 Heldt, 1938, p. 122. 

 Occurrence. St. WS 997, 50-0 m. 



