And other British prawns. 



11? 



These deviations from the normal are of some interest, since 

 systematic importance has been attached to the numbers of these 

 feathered setse, and the presence of more than two of them has 

 been given as one of the principal characters of the genus Allo- 

 caris Sollaud. It is evident tliat it possesses neither generic nor 

 specific importance. Pesta* has already shown that Sollaud's 

 genus is untenable on this and other grounds, and states that he 

 has found four setie in the telson of P. varians from Albufera. 



Text-figure 4. 



Telson. 



A. Falcemonetes varians with supernumerary pair of dorsal set^. 



B. „ „ „ four supernumerary ventral setae,. 



C. P. varians from Algeria. 



D. L. squilla with three ventral setse. 



E. L. serratus with additional spine and four ventral seta;. 



I possess specimens from Algeria which likewise all have four 

 setae. 



The frequent presence of supernumerary setse in P. varians is no 

 doubt a primitive character, or perhaps more precisely a retention 

 of a larval character comparable to the non-development of 

 a mandible palp. 



In the British species of Leander the telson varies very little, 

 but supernumerary feathered setse are occasionally met with. 



* Ann. K.K. Naturh. Hofmus. Wien, xxvii. (1913). 



