100 



MR. R. GURNEY ON LEANDER LONGIROSTRIS 



the fused * part, whereas in L. serratus it is considerably 

 longer. 



Antennule. — The short flagellum is about one-seventh shorter 

 than the peduncle, and the fused part one-quarter or one-fifth of 

 its total length. 



Text-figure 1. 



Rostrum. 

 A. Leander longirostris. B, C. Xi. longirostris with unusual number of 

 teeth. D. JPalcemonetes varians. E. L. sqnilla. F. L. adspersus. 

 G. L. serratus (adult). H. L. serratus (young, 15 mm. long). 



Second Leg. — Dactylus nearly half the length of the chela ; 

 carpus shorter than the chela or the merus. 



Distribution. — This, the so-called " Common " Prawn, is a 

 littoral species, preferring, but not confined to, weedy and rocky 

 ground. It is abundant on the south coast of England and on 



* The inner, shorter, branch of tho outer flagellum is usuallj' described as being 

 fused to the outer branch for part of its length, and the terms "fused " and " free " 

 part are convenient and intelligible. But the " free " part is clearly shown in 

 development to be a secondary or accessory outgrowth of the basal, sensory, part 

 of the flagellum. The basal part, plus the accessory flagellum, is here spoken of as 

 the "shorter flagellum" simply for convenience of description. 



