1906.] CRUSTACEA OF THE THIRD TANGANYIKA EXPEDITION. 205 



the characters of the Macrura seem to me to point in the direction 

 of some such explanation as that which has been suggested by 

 Mr. Boulenger in the case of the fishes, namely, that the forms 

 now inhabiting the lake are the result of divergent evolution and 

 specialisation during a very long period while the lake was quite 

 isolated. 



EXPLANATION OF PLATES XI.-XIV. 



Plate XI. 



Fig. 1. Talcemon moorei (p. 188), second perajopod of female. Total length of body 

 27 mm. la. Portion of same, further enlarged. 



2. LimnocaricUna retiarius (p. 182), female. Cephalothorax from the side. 



3, „ female. Antennal scale. 



4_' " „ „ Perseopod of first pair. _ 



5' " jj „ Perceopod of second pair. 



el " ," „ Pereeopod of fourth pair. 6 a. Dactylus 



of sam.e, further enlarged, 

 y ^^ „ Perffiopod of fifth pair. 7 a. Dactylus of 



" " same, further enlarged. 7 h. Spines of 



dactylus. 

 8 „ )) " Tail-fan. 



9". Limnocaridina parvula (p. 193), female. Cephalothorax from the side. 

 10. „ „ female. Perajopod of first pan-._ 



11" " ,, „ Perffiopod of second pair. 



12] " „ „ Pera^opod of fourth pair. 12 a. Dactylus 



of same, further enlarged. 

 13_ ^^ ,, ,. Perffiopod of fifth pair. 13 a. Dactylus 



of same, further enlarged. 

 Tail-fan. 



14. 



Plate XII. 



Fig. 15. Limnocaridina similis (p. 195), female. Cephalothorax from the side. 

 16. ,, female. Antennal scale. 



17* " „ „ Per;Gopod of first pair. 



lg| " ,j „ Pera^opod of second pair. 



19' " „ „ Peraiopod of third pair, dactylus. 



20! ," „ „ Per;eopod of fifth pair. 20 a. Dactylus 



of same, further enlarged. 

 21. „ male. Perajopod of third pair. 21a. Dactylus 



of same, further enlarged. 

 22 „ J, female. Tail-fan. 



23.' Limnocaridina latipes (p. 196), female. Cephalothorax from the side. 

 24. ,, female. Antennal scale. 



25^ " „ „ Perffiopod of first pair. _ 



26* " „ „ Perceopod of second pair. 



27' " ., „ Pei-c-eopod of fourth pair. 27 a. Dactylus 



of same, further enlarged. 

 28. „ >; " Perffiopod of fifth pair. 28 a. Dactylus 



of same, further enlarged. 

 29 „ J) " Tail-fan. 



30! Limnocaridina socins (p. 196), female. Cephalothorax from the side. 

 31. j^ „ female. Antennal scale. 



32' ", „ „ Peraaopod of first pair. 



33 ., „ Perceopod of second pair. 



34'_ '^ „ ,, Peraiopod of fourth pair. 34 a. Dactylus 



of same, further enlarged. 

 35_ j^ „ male (smaller specimen). Dactylus of fourth peraio- 



pod. 



36. ,, „ female. Peraiopod of fifth pair. 36 a. Dactylus of 



same, further enlarged. 



37. „ „ » Tail-fan. 



