I. '08. 121 



scales and antennulea ai'o pale red dorsally, paler still 

 below. The last four joints of the first pair of pereiopods are 

 red above, fading beneath to an ivory white; the remaining 

 legs are white, sometimes tinged with red. 



Size. — The largest specimen examined is a male measuring 

 43 mm. ; the large right-hand chela of this individual is fully 

 31 mm. in length. 



General distribution. — Mediterranean and Adriatic (Milne- 

 Edwards, Heller, etc.), Algerian coast (Lucas), Bay of Biscay 

 (Fischer). In the English Channel it is known from the 

 coasts of Devon and Cornwall (Norman, etc.). 



Coutiere is of the opinion that Alpheus Halesi, Kirk, is 

 probably a synonym of this species ; if this is so, the horizontal 

 range of A. ruber extends to New Zealand. 



Iiish distribution. — This species has only been found on a 

 few isolated occasions in Irish waters, but its rarity is perhaps 

 more apparent than real. 



It was first discovered by Melville (1860) in 60 fathoms off 

 the Arran Is., Co. Galway. In June, 1905, a second speci- 

 men was found in the same district ; it was obtained by a 

 sailing trawler in the North Sound, between Inishmore and 

 the mainland. The remaining records are : — 



Helga. 



R. 10— 3/5 /'05.— 15 miles off Mine Head, Co. Waterford. 41-42 

 fathoms. Trawl — One, 43 mm. 



S. 361— 20/2 /'06.—13i miles W.iS. of Chicken Rock, Isle of Man. 

 35J-36 fathoms. Trawl. Temperature at 35 fathoms 

 7-0° C, sahnity 34-057^^— One, 23 mm. 



S. 560 and 561— 24/10 /'07.— 12-15 miles W.S.W. of Chicken Rock, 

 Isle of Man. 34J-42 fathoms Trawl. Temperature at 30 

 fathoms 12-75° C, salinity 34-047^^— Eighteen, 34-42 

 mm. 



The trawling grounds off' the east coast of Ireland have been 

 fished again and again, but Alpheus ruber has only been 

 found on the occasions mentioned above. Apart from the in- 

 terest afforded by the occurrence of the species in compara- 

 tively large numbers at a single point in a large and ap- 

 parently uniform area, the records are valuable as constituting 

 the most northern limit of its known horizontal distribution. 



In the Irish Sea the specimens were found on a bottom of 

 soft mud, whereas the Waterford and Galway examples were 

 taken on rough stony ground. 



Vertical range. — Alpheus ruber is usually found in about 30 

 or 40 fathoms of water. It has been recorded from 61 

 fathoms in the Mediterranean (Adensamer). 



