248 CEYLON PEARL OYSTER REPORT. 



The 2nd, 5th, 10th and 11th joints bear spinous projections. Male right anterior 

 antennas 23-jointed, with a geniculation between the 18th and 19th joints. 



Abdomen of female 4-jointed ; of male 5-jointed, the last joint very small. Furcal 

 rami slightly curved inwards, about twice as long as the width. Fifth natatory 

 legs attenuated ; the second joint of right leg- in female has a long plain projecting 

 spine on inner side. The chela of the male right natatory leg is clothed with short 

 hair on the outer side. 



The other appendages are similar to those of < '. typicus. A number of specimens, 

 male and female, were taken in Palk Straits, Ceylon. 



The species is easily distinguished by the median dorsal cephalic hook, and by the 

 5th pair of natatory legs and the abdomen and furcal rami. 



Isias clavipes, Boeck. 



This British species was only taken once, in the first gathering. It ranges to the 

 Mediterranean and Atlantic Ocean. 



Pseudodiaptomus salinus, Giesbr. Plate II, figs. 21 to 23. 



Occurred at 3 stations in the Gulf of Suez and at 3 stations in the Indian Ocean, 

 its only previous record being from the Red Sea. 



Giesbrecht's specimen was a female, the male remaining unknown until now ; we 

 have the satisfaction to record it from the same stations at which the females were 

 found. The male measures 1'25 millims., and its characters are shown by figs. 22 

 and 23, on Plate II. The female also measures 1"25 millims., and its fifth pair of legs 

 are shown at fig. 21, Plate II. 



Pseudodiaptomus serricaudatus (T. Scott). 

 Occurred at 20 stations throughout the Indian Ocean and about Ceylon. 



Pseudodiaptomus aurivillii, Cleve Plate II., figs. 24 to 26. 



Found at 8 stations in the Indian Ocean. Fortunately the specimens include the 

 male hitherto unknown. The female measures 1'2 millims. and the male "93 millim. 

 The characteristic appendages of both sexes are shown by figs. 24 to 26, on Plate II. 



Temoropia mayumbsensis, T. Scott. 



Two records for this rare species were added in the Gulf of Suez. The Gulf of 

 Guinea is its only previously known habitat. 



Temora longicornis (Muller). 

 This common British species was found at 2 stations, from the English Channel 

 to the Mediterranean. 



Temora discaudata, Giesbr. 

 One of the most widely distributed species throughout the regions traversed. 



