108 MR. R. GURNBY ON LEANDER LONGIROSTRIS 



dacbylus and p^ti-fc of the palm. The dactylus is long and slender, 

 more than three-quarters of the length of the pahii. The carpus 

 usually considerably exceeds the length of the merus, but may be 

 of the same length. 



De Man has separated this species into two forms : — 



L. c(dspersus (Rathke). Black Sea. 



L. adspersus var. fabricH (Rathke). Scandinavia, Baltic, 



Denmark, France, Adriatic, Mediterranean, British 



Isles. 



The chief differences are as follows : — 

 Rostrum usually with 4 ventral teeth ; shorter ramus of anten- 

 nule usually projecting by g to ^ its length beyond rostrum. 



L. adspersus. 

 Rostrum usually with 3 ventral teeth ; shorter ramus projecting 

 usually by more than ^ its length beyond rostrum. 



L. adspersus Y&Y.fahricii. 



Distribution in British Isles. — Bell described the species under 

 the name of P. leachii from specimens taken in Poole Harbour. 

 Mr. J. Omer Cooper has kindly sent me a collection of prawns 

 from this estuary, which proved to be made up as follows : — 



L. serratus 528 



L. adspersus 9 



L. squilla 5 



It is evident that L. adspersus is by no means an abundant 

 species. Mr. Kemp has recorded it from two localities in Co. 

 Galway, in one of which it occurs in company with L. squilla and 

 L. serratus as it does at Poole, and he notes that it has been taken 

 also at Weymouth and in the Thames estuary. I have myself 

 taken two small specimens from between tide-marks at Burnham- 

 on-Crouch, and have had others sent to me from West Mersea, 

 where it is known as the " Mud Prawn," and is taken in some 

 numbers by eel-catchex"S. It is an estuarine species, prefei^ring 

 a muddy bottom, but Mersea seems to be about its northern limit, 

 as I have not found it in the Stour or the Orwell, and it certainly 

 does not occur in Breydon Water in Norfolk, where conditions 

 would seem to be favourable. 



4. Leander LONGIROSTRIS Milne Edwards. (Text-fig. 3.) 



P. longirostris M. Edwards, Hist. Nat. des Orustaces, ii. 1837, 

 p. 392. 



P. edwardsi Heller, 1863. 



L. longirostris De Man, 1916, p. 149. 



There has been some confusion in the vise of the name 

 L. longirostris, since not only did Milne Edwards describe two 

 distinct species under the same name, but, by a misplacement of 

 a footnote reference, even the authority of the name was wrongly 

 referred to Sav. Milne Edwards himself corrected his second 



