AND OTHER BRITISH PRAWNS. 101 



some parts of the Irish coast, but it is by no means common on 

 the East Coast north of the Thames. Murie* has given an 

 excellent account of the distribution of this prawn, to which 

 I can add little. The shrimpers from Southend and from 

 Burnham-on-Crouch bring in fair numbers of them, but at West 

 Mersea they are much more rare. I have been to sea with one 

 of these shrimpers and saw only one prawn in a catch of 12 

 gallons of '' Pink Shrimps" (Pa?idahis montagai). At Harwich 

 also the prawns brought in are so few as to be hardly worth the 

 trouble of separating them from the shrimps. They are said to 

 be taken at times in some numbers in the Orwell and Deben, and 

 I have myself taken them as far up the Deben as Woodbridge. 

 At Aldeburgh the species is so rare that a fisherman who took 

 one among his shrimps in 1921 had never seen one before ! Off 

 Yarmouth the capture of prawns is exceptional, though a few are 

 sometimes taken on the sandy ground close inshore, and I have 

 myself seen specimens taken on Breydon Water. At Lynn it 

 appears to be almost unknown. 



L. serratus has been recorded from Oresund (Denmark), a,nd is 

 found on the coasts of Holland, Belgium, France, and the Channel 

 Islands. In the Mediterranean it occurs in " prodigious 

 quantities " on the coast of Algeria (Lucas), and inhabits the 

 shores of Italy, Greece, and the Bosphorus. 



It is therefore a southern species, which is only a straggler in 

 the North Sea. 



Breeding-period. 



Whereas the other species of British prawns breed during a 

 well-defined period in summer, the breeding-period of L. serratus 

 seems to extend through winter and to continue till midsummer. 

 In the List of the Plymouth Marine Invertebi'ate Fauna t it is 

 recorded as breeding from November to June, but egg-bearing 

 females may still be found in July. I have little personal acquaint- 

 ance with this species, since it is so rare off the Norfolk coast, 

 but it seems to me that the few published records indicate that 

 L, serratus may prove to have a breeding-habit somewhat similar 

 to that of Crangon vtdgaris. In this species Ehrenbaum J found 

 two main periods of egg-laying — namely, April- J une and October- 

 November. The autumn -laid eggs took 4 to 5 months to develop, 

 and hatched from February to April, while those laid in summer 

 hatched in about 4 weeks — i. e., from May to August. 



Larvse of L. serratus are found in very small numbers in the 

 plankton from December onwards. 



Owing to the difference in the breeding period, any Leander 

 larvse found off British coasts from December to nearly the end 

 of June may confidently be assigned to L. serratus. 



* Report on the Sea Fisheries and Pishing Industries of the Thames Estuary, 

 p. 247. London, 1903. 



t .Tourn. M. B. A. vii. (1904). 



X Mitth. der Sekt. liir Kusten und Ilochsectischerci, Jg. 1890. 



