282 



ON BRANCHIURA FROM LAKE TANGANYIKA. 



of fish in Tanganyika is so great (some 101 out of 115) it is not 

 surprising that they constitute a majority of the actual hosts. 

 Still there is no reason to suppose that there is any significance 

 in such a connection from what we know of the habits of these 

 parasites, and we find, in fact, an endemic Argulus^ living on a 

 widely distributed host, and widely distributed Argulids (Bolops 

 ranarum and Argulus afrioamis) living in Tanganyika on endemic 

 fish. 



Not infrequently two species were found living together on a 

 common host. It is remarkable that Bolops ranarimi was almost 

 invariably found associated with Argulus africanus. On the 

 only occasion on which the former was obtained in Tanganyika, 

 it was, as usual, accompanied by individuals of the latter. 

 While one is hardly prepared to say that there is a real signi- 

 ficance in this association, it is certainly strange that these two 

 widely distributed forms should appear to range together in the 

 localities from which they come. There *is no such constancy 

 in the occurring together of other types. A. ruhropuitctatus, 

 though taken on several difierent occasions, was always found 

 alone. 



The question of distribution within the limits of each lake 

 was hardly likely to prove interesting. Apart from forms 

 obtained on a single occasion, tliere is no evidence that any of 

 the species are confined to a particular region. 



EXPLANATION OF THE PLATES. 



PXATE XLI. 



Fig. 1. Argulus incistis (p. 268). Male, dorsal view. X 5§. 



2. „ „ Female, dorsal view. X 5i, 



3. Arffulus ruhropunctatus (p. 269). Female, dorsal view. 



4. „ „ Male, dorsal view. X 5. 



5. „ „ Male, ventral view. X 5. 



6. Argulus personatus (p. 271). Male, dorsal view. X 6. 



7. „ „ Female, dorsal view. X H. 



8. „ „ Female, ventral view. X 4^. 



X5h 



Plate XLII. 



Fig. 9. Argulus exiguus (p. 272). Male, dorsal view. X 6. 



10. Argulus angusticejps (p. 273). Female, dorsal view. X 5|. 



11. „ „ Female, ventral view. X 5^. 

 12 Argtdus striatus (p. 274). Female, dorsal view. X 6. 



13. '„ „ Male, dorsal view. X 6. 



14. ,, ,, Male, ventral view. X 6 J. 



15. Argulus ruhescens (p. 276). Female, dorsal view. X 6|. 



16. „ „ Male, dorsal view. X 6|. 



PlATE XLIII. 



Fig. 17. Argulus incisus (p. 268). Antennule and antenna. X 60. 



18. „ „ Maxilliped. X 50. 



19. Arguhis ruhropunctatus (p. 269). Antennule and antenna. 



20. „ „ Maxilliped. X 30. 



21. Argulus exiguus (p. 272). Antennule and antenna. X 100. 



22. „ „ Maxilliped. X 100. 



X40. 



