74 CEYLON PEAKL OYSTER REPORT. 



Kaltura (Station XLTII), 2 ? , 35 millims. and 48 millims. ; Pearl banks, Gulf of 

 Manaar (Station III.), 1 ? , 48 millims. ; Aripu Reef (Station LXIV.), 1 <?, 35 millims. 



All the specimens are much damaged, the exoskeleton apparently being poorly 

 calcined. In all the female specimens the thoracic legs are incomplete. 



In the male the petasma is comb-like as described by Sp. Bate. The antennular 

 flagella, which were absent in the "Challenger" specimen, are typical of the genus. 

 Tliere are two long flagella on each antennular peduncle, the upper one being thin and 

 the lower being very broad. The antennal scale is well developed and is longer than 

 the antennular peduncle and twice as long as the antennal peduncle. The antennal 

 flagellum is long and is slightly thicker than the upper antennular flagellum. The 

 form of the rostrum and carapace agrees with Spence Bate's description. In the 

 " Challenger" specimen the 3rd maxillipeds and the thoracic legs were absent. 



In the Ceylon specimens the 3rd maxillipeds are very long, reaching well in front 

 of the antennal scale. The distal end of the propodite is about on a level with the 

 end of the antennal scale. All the joints are richly covered with setae, some of 

 which are so robust as to have the appearance of long slender spines. Of the thoracic 

 legs the first is the shortest and only reaches to the end of the carpos of the 3rd 

 maxilliped. The second leg reaches to the end of the propodite of the 3rd maxilliped. 

 The third pair is missing. The fourth is very long and slender, reaching almost as 

 far forward as the end of the 3rd maxilliped. The last pair of thoracic legs are short, 

 being only slightly longer than the 1st pair and more slender. 



Comparative lengths of appendages in male specimen : 



3rd maxilliped 12 millims. 



1st thoracic leg 9 ,, 



2nd 11-5 



3rd (wanting) 



4th thoracic leg 14 millims. 



5th 10' 



General distribution : Papua, Ceylon. 



Sicyonia, Milne-Edw., 1830. 



Sicyonia lancifer (Olivier). 



Palaemon lancifer, Olivier, ' Encyclop.,' t. vi., p. 664. 

 Sicyonia lancifer, de Haan, 'Fauna Japonica,' p. 194, 1849. 

 Sicyonia lancifer, Sp. Bate, ' " Challenger" Macrura,' p. 297, 1888. 



Locality : Pearl banks, Gulf of Manaar (Station III.), 3 ? and 1 c?, average length 

 40 millims. 



There is very little to add to Spence Bate's description and figures. 



In the male the petasma is symmetrical, and there is a conspicuous triangular plate 

 between the bases of the last three pairs of thoracic legs, having the apex produced 



