I. '08. 138 



Crangon vulgaris has been recorded from the E. coast of N. 

 America and from several locaHties in the Pacific, but these 

 specimens are in all probability referable to C. septemspinosa, 

 Say, an extremely closely allied form, which differs from C. 

 vulgaris only in the shape of the antenna! scale (v. Eathbim, 

 1904). 



Irish distribution. — Abundant all round the coast, more espe- 

 cially on a sandy bottom. 



Vertical range. — Common off the Irish coast in 0-10 fathoms, 

 and more rarely found up to 20 fathoms ; in the Christiania 

 fjord it has occurred in 30 fathoms (G. 0. Bars) and in the 

 Brevik Fjord in 50-65 fathoms (Wollebaek). In the West 

 Atlantic it has much the same range ; Kingsley (1878) states 

 that it is common in 70 fathoms. 



Crangon AUmanni, Kinahan. 



Crangon AUmanni, Kinahan, 1857. 

 Steiracrangon AUmanni, Kinahan, 1861, fig. iii. 

 Crangon AUmanni, Sars, 1890, PI. i, figs. 29-31 (develop- 

 ment). 

 Crangon AUmanni, Wollebaek, 1908, PL viii, figs. 1-50. 



This species is very closely allied to C. vulgaris, but may be 

 easily distinguished by the deep longitudinal groove and parallel 

 carinae on the dorsal aspect of the sixth abdominal somite. 

 The rostrum also is slightly narrower than in the preceding 

 species and the outer antennular flagellum of the female 

 reaches considerably beyond the apex of the antennal scale 

 (v. Wollebaek, 1908). 



Colour in life. — The carapace and abdomen are brownish 

 grey, composed of thinly distributed brown, with occasional 

 yellow chromatophores, frequently verging to a dark maroon 

 tint on the telson and uropods. Occasionally the general 

 colouring inclines to reddish. The eyes are greyish black. 

 The pereiopods, more particularly the last two pairs and the 

 propodus of the first pair, are dotted with red chromatophores. 

 The gastric and cardiac regions are very dark and usually 

 show conspicuously through the carapace. 



Size. —The largest specimen examined, an ovigerous female, 

 measures 58 mm. 



Were it not for Sars' important contribution to the life his- 

 tory of this species, one would be inclined to follow Ortmann 

 in regarding the characters of C. AUmanni as merely of sub- 

 specific value. Sars has, however, shown that the two forms 

 are easily distinguishable at a very early stage. Larval C. 

 vulgaris possess a strong backwardly directed spine on the 

 third and a pair of lateral spines on the fifth abdominal somite. 

 In larval C. AUmanni the spine on the third somite is obsolete 

 o.nd the pair on the fifth much shorter. 



