122 



MR. R. eURXET ON LEANDER LONGIROSTRIS 



The variety mesogenitor Sollaud* occurs in Tunisia, and I have 

 a few specimens, taken in the stream flowing from the Sources 

 D'Oumach,near Biskra, in Algeria, which would probably belong 

 to this variety. They are all small, not exceeding 24 mm., but 

 include four adult males, while the females appeal- also to be 

 fully grown. While the females differ to some extent from 

 Norfolk specimens in the relative length of the joints of the 

 second leg and the proportions of the short flagellum of the 



Text-figure 6. 



Falcemonetes varians. 

 A and B. Posterior and anterior views of appendix masculina of two 



specimens from Algeria. 

 C. Appendix masculina of specimen from Essex. 31 mm. 



antennule, the material is not sufficient to justify any definite 

 conclusion as regards varietal or specific differences. It is other- 

 wise with the males. In all these four males there are two 

 characters which very distinctl}^ se} arate them from the brackish- 

 water representatives of the species. These are : — 



(1) The appendix masculina of the second pleopod is slender, 

 and extends by nearly half its length beyond the inner branch of 

 the pleopod. There is a group of strong spines at its apex, but 

 the sides and anterior face are bare or armed with only one or two 



* Sollaud, C. R. Acad. Sci. Paris, t. 155, p. 1268 (1912). 



