i8z DISCOVERY REPORTS 



REPORT ON THE MYSIDACEA COLLECTED DURING A SURVEY OF 

 THE BENGUELA CURRENT BY R.R.S. 'WILLIAM SCORESBY', 



4-14 MARCH 1950 

 During the course of a first survey of the Benguela Current by 'William Scoresby' in March 1950, 

 mysids were captured at twelve stations off the west coast of South Africa, from west of the Orange 

 River estuary to the latitude of Walvis Bay. Surprisingly few specimens were taken, apart from a haul 

 containing over 450 specimens of the gregarious Gastrosaccus sanctus at station WS 1002. In spite of 

 the few numbers, the collection has proved to be very rich, ten genera being represented and sixteen 

 species, one of which is new to science. In addition there were a few specimens, which may represent 

 other genera and species, but they were either too young or too damaged to be identified. I have been 

 particularly struck by the large proportion of very small specimens, in many cases measuring only 

 2 mm. or 3 mm. and some so small that they must only just have been liberated from the brood pouch. 

 This must be due in part to the type of gear used, and especially to the meticulous care of Dr T. J. 

 Hart, who dealt with the hauls and sorted the catch. 



Full details of the stations and the names of the species captured at each are given at the end of the 

 list of ' William Scoresby ' stations. 



Occurrence : Eucopia e rimaldii Nouvel - *94* 



St. WS 986. 10. iii. 50 (day). 1000-750 m., 1 very small juv. 



Distribution. Within the known geographical range of this species. 



, )ccurrence: Boreomysis rostrata Illig, 1906 ■ 



St. WS 976. 6. iii. 50 (day). 750-500 m., 1 small juv., 3 mm. 



St. WS 977. 6/7. iii. 50 (night). 750-500 m., 1 juv. $. 



St. WS 978. 7. iii. 50 (day). 750-500 m., 3 9?, 9'4~ 12 mm - 



St. WS 986. 10. iii. 50 (day). 50-0 m., 1 adult cJ, 14-5 mm. 



Distribution. Within the known range for the species. 



Occurrence: Boreomysis microps G. O. Sars, 1884 



St. WS 996. 12. iii. 50 (day). 1000-750 m., 1 imm. $, in two pieces, estimated length 10 mm. 

 Distribution. Within the known range for the species. 



Occurrence : Boreomysis insolita sp.n. 



St. WS 979. 7. iii. 50 (night). 100-50 m., 1 adult 9> 8-2 mm., 3 imm. 99- 



St. WS 987. 10. iii. 50 (day). Two hauls: 50-0 m., 1 adult 6*, 9 mm., 1 imm. <J, 7-6 mm., 1 imm. 9, 7-3 mm., 3 juv. ; 

 250-100 m., 3 adult ^ ^ 8-2 mm., 3 imm. gg, 4 adult 99. 8-4 mm., 3 imm. 99. 4 juv., 10 small larvae. Types. 



Distribution. West and south-south-west of Walvis Bay. 



q Gastrosaccus sanctus (van Beneden), 1861 



St. WS 1000. 13. iii. 50 (night). 100-50 m., 1 very small juv. 



St. WS 1002. 14. iii. 50 (night). 50-0 m., 20 adult <$$, 24 adult 99 (ovig.), largest 9 mm., over 350 juv., 3-7 mm. 



Distribution. West of Orange River estuary, shallow water. This is considerably farther south 

 than previous records although one specimen was taken off South Georgia by R.R.S. 'Discovery' at 

 station 149. 



