I. '08. 16 



on its upper face near the distal end, situated in a sort of 

 recess overhung by the thickened inner anterior portion. 



On the first maxillipede (fig. 4) : a bright bhie patch at 

 the inner side of the apex of the exopod. 



On the third maxillipede (fig. 12) : a granulated suffusion 

 on the upper half of the ischium and on the basus, a denser 

 granular patch at the distal end of the merus and propodus, 

 a similar but very dense patch at the apex of the carpus 

 and a rather obscure spot near the base of the dactylus. 



On the first three pereiopods (figs. 9-11) : a dense 

 granular patch on the propodus just behind the insertion of 

 the dactylus, a similar patch (very strongly marked on the 

 first pereiopod) at the distal end of the carpus and another 

 of a less defined character at the distal end of the merus, 

 the latter having in addition another small patch or streak 

 at the proximal end of the same segment. 



On the fifth j^ereiopods : a single spot behind the coxal 

 articulation. 



Blue pigmentation is of great rarity in deep-sea shrimps, 

 although not a very uncommon feature of the ova of certain 

 Caridea (chiefly Pandalidae). The only instance that I am 

 av^are of, apart from cases in which it is associated v^ith 

 luminous organs, is Benthesicymus Tanneri, Faxon (1895, 

 PI. II.). This species, which is very closely allied to A. 

 elegans, has j^eculiar patches of deep blue pigment on the 

 dorsal surface of the abdomen. In the present state of our 

 knowledge it does not seem at all probable that these are 

 luminous. 



The fact that small specimens of A . elegans possess relatively 

 more of the blue pigment than older examples is rather antag- 

 onistic to any theory of its being directly involved in a luminous 

 function, for the photophores of A. dehilis increase in number 

 with age. Unfortunately the specimens found off the Irish 

 coast are invariably dead when caught, so that no direct ob- 

 servation is possible. For the present the question must 

 remain undecided, until more is known of the association, 

 which apparently exists, between blue pigment and a luminous 

 function. 



General distribution. — Amalopenaeus elegans seems to be 

 very widely distributed in the N. Atlantic. It has been re- 

 corded from the east coast of N. America from between lat. 

 31° 41' and 41^13' N., long. 66° 0' and 76^12' W. (Smith); 

 from West Greenland (lat. 65° 25' N., Hansen); from Davis 

 Straits and the neighbourhood of Iceland (Hansen) ; from the 

 Sargasso Sea and near the Cape Verde Is. (Ortmann and Bou- 

 vier) ; from the Bay of Biscay (Kemp) and N.E. Atlantic (lat. 

 52° 18' N., long. 15^53' W., Caiman). In the Mediterranean 

 it has been found in the Straits of Messina and near Naples 

 (Lo Bianco), and in other localities (Bouvier). 



As suggested by Hansen (1908), it is probable that this 

 species never occurs in temperatures below 0°C., although it 

 doubtless exists in warm layers overlying .water below freezing 

 point. 



