I. '08. 131 



Size. — L. serratus is the largest of the thre€ British species 

 and frequently attains a length of 100 mm. or more. 



General distribution. — Leander serratus has been recorded 

 from the Danish and Dutch coasts (Meinert), from Belgium 

 (van Beneden), from both north and west coasts of France 

 (Milne-Edwards, Barrois, Fischer, etc.) and from the Medi- 

 terranean (Heller, etc.). It is found abundantly off the Eng- 

 lish coast, more particularly in the south ; off the Scotch coast 

 it is apparently very rare (Herdman, 1880, records P. serra- 

 tus? from Lamlash Bay). 



Irish distribution. — This species is abundant on most parts 

 of the Irish coast. As at present understood its range ex- 

 tends as far north as Larne, Co. Antrim (Rankin), on the east 

 coast and as far as Blacksod Bay, Co. Mayo, in the west. In 

 the south-east, south and west it occurs plentifully and, 

 although it has not as yet been noticed in the north, it is very 

 probable that it will be found there in course of time. 



Vertical range. — Essentially a littoral species. 



Leander adspersus (Rathke). 

 PI. XX, figs. 2, a-e. 



Palaernon Leachi, Bell, 1853, fig., p. 307. 

 Palaemon Fabricii, Mortensen, 1897 (development). 

 Leander adspersus, Senna, 1903 (ubi sijn.). 



The pigment spots which Bell mentions on the lower blade 

 of the rostrum (fig. 2a) afford a ready and certain means of 

 separating this species from its allies when alive. The colour- 

 ing is fairly permanent in weak formalin but disappears rapidly 

 in spirit. 



Size. — The largest specimen examined measures 65 mm. 



Leander adspersus is by far the rarest of the three British 

 and Irish species, but in Norway it is found in great abund- 

 ance and is fished commercially with considerable profit. 



General distribution. — L. adspersus is known from west 

 and south Norway (Sars, Wollebaek, etc.), from Sweden 

 (Goes), from Denmark (Meinert), from the Prussian coast 

 (Zaddach), from the west coast of France (Fischer), in the 

 Mediterranean and Adriatic (Heller, Adensamer, etc.) and in 

 the Black Sea (Czerniavsky). In the English Channel it has 

 been recorded from Poole Harbour (Bell) and Weymouth (W. 

 Thompson) and has also been found in the Thames estuary. 



Irish distribution. This species was first recorded from the 

 Irish coast by Melville (1860) from Gal way Bay. During the 

 last two years it has frequently been found in the same dis- 

 trict, near Oranmore, Co. Galway, where it occurs in 

 company with L. squilla and L. serratus. The only other Irish 



