I. '08. 38 



Colour hi life. —The carapace and abdomen are perfectly 

 clear and transparent, with the exception of a red spot or 

 aggregation of spots near the posterior edges of the second 

 to fifth somites inclusive ; the sixth somite has a red dorsal 

 stieak on its posterior half and another similarly situated on 

 the ventral aspect. The eyes are black, with a dull reddish 

 reflection. The antenna and outer flagellum of the antennule 

 are dotted with small red spots, a few of which are also pre- 

 sent on the inner antennular flagellum ; the peduncle and an- 

 tennal scale are colourless. The first and second pairs of 

 pereiopods are transparent, with a red streak or row^ of spots 

 along the under side of the basus, ischium, merus and: carpus ; 

 the digits are suffused with red, and in the first pair there is 

 an additional red spot at the base of the propodus. The third 

 pair is transparent ; the fourth shows red spots on the ischium 

 and merus ; the fifth is similar, with red spots, in addition, on 

 the carpus. At the base of each pereiopod there is a red spot 

 on the sternum. The basal joint of the pleopods is marked 

 with a red spot or streak and the tips of the rami are some- 

 times tinged with the same colour ; the distal third of the outer 

 uropods is also red. The eggs are quite transparent or very 

 faintly greenish. 



This description details the maximum development of red 

 pigment observed ; in many specimens it is restricted to only 

 a few of the areas noted above. In no case is there enough 

 red colouring present to detract from the general invisibility 

 of the animal in the water ; a feature which has gained for 

 P. sivado the suitable name of " ghost prawn." 



General distribution. — This species is well known in the 

 Mediterranean (Heller, etc.), and has been found rather com- 

 monly off the Portuguese coast (Wolfenden, 1906) and in the 

 Bay of Biscay ; it is apparently quite absent from the English 

 Channel and North Sea. It has been taken in the Bristol 

 Channel and is frequent off the west coast of Scotland (Scott). 

 In Norway it is found rarely off the south and west coasts (Sars 

 and Norman). The only extra-European record is from the 

 neighbourhood of India, where three specimens have been re- 

 corded from the Andaman Sea and Bay of Bengal (Alcock). 



Irish distribution. — Adult P. sivado are found fairly com- 

 monly throughout the Irish Sea in soundings of 20 fathoms or 

 more ; post-larval specimens are sometimes found at much 

 shallower depths (8-9 fathoms). The species is always to be 

 found in the area known as Lambay Deep, where the sound- 

 ings range from 50 to 73 fathoms. Like Pandalus Montagui 

 and Megajvijctiphanes norvegica it is soijjetimes found in as- 

 tonishingly large numbers ; these assemblages appear, how- 

 ever, to be quite temporary. P. sivado has not so far been 

 taken off the south coast of Ireland and in the west is quite 

 scarce and confined to deep water; the records are : — 



Helga. 



15/7/'03.— 53° 34' N., 11° 31' W., 110 fathoms. Trawl— Three 

 11-5-14 mm. 



