68 Proceedings of the Royal Physical Society. 



VII. — On the Distribution of the Thorny Lobster (Palinurus vulgaris) 

 in British Waters. By James Ritchie, M.A., B.Sc, Natural 

 History Department, The Royal Scottish Museum. 



(Read 22nd November 1909. Received 10th January 1910.) 



This note is an effort to dispel, in one instance, the haziness of knowledge 

 which shrouds the limits of distribution of even common British marine 

 invertebrates. 



The Thorny Lobster — Palinurus vulgaris, Latreille (P. elephas (Herbst) )■ — 

 otherwise known on the coasts of Britain as the Spiny Lobster, Rock Lobster, 

 Eed Crab, Craw-fish, even as the Long Oyster, and in Europe as the 

 Langouste, is a southern form, very common, according to d'Orbigny, on 

 the rocky parts of the southern and western coasts of France, occurring also 

 on the shores of Algeria, especially in the roadsteads of Algiers and Oran. 

 Its distribution from this southern centre is not a wide one, for, as we pass 

 northwards, it gradually drops out of existence ; so that in fixing its British 

 distribution we practically fix at the same time the limits of its dispersal to 

 the north. 



General accounts of British Crustacea agree in allotting to the Thorny 

 Lobster a vague area on our southern and western coasts, none being more 

 definite than that of Bell : " This fine species is an inhabitant of our western 

 coasts, where it occurs in great numbers, and from whence it is brought in 

 considerable quantities to the London market. It is much esteemed as an 

 article of food, although certainly of inferior flavour to the lobster. It is 

 but sparingly found in the north, whether of England or Ireland, but is equally 

 common on the southern coasts of both." 1 



Of its abundance on the south coast of England there are many records. 

 It is " taken in large quantity all round the coast [of Cornwall] and at Scilly, 

 and ranks in importance with the Lobster and the Edible Crab. Though 

 often found inshore it is most plentiful, of largest size, and of finest condition 

 in deep waters, where its most congenial haunts are on rocky and on 

 ' scuddy ' ground, in shady lanes among rocks, and indeed where sand and 

 rock come together." 2 Eastward from Cornwall it appears to be scarcely so 

 abundant, for although it is common in the neighbourhood of Plymouth, 3 



1 T. Bell, A History of the British Stalk-eyed Crustacea, London, 1853, p. 215. 



2 J. Clarke, Zoologist, Aug. 1909, p. 303. 



8 Marine Biological Association, "Plymouth Marine Invertebrate Fauna," 1904, p. 252, 

 Jniir. Mar. Biol. Ass. (n s.), vii. 2. 



