FAUNA OF THE AFRICAN LAKES. 



555 



Table of Distribution of MaG?m7-af. 



L-u • Taugan- Victoria Albert Edward 



Nameofbpec.es. ^.^^^ ^y^rr.ii. ^^^^^^^ Nyanza. Nyanza. 



Family Pal^monid-s;. 



Palfemon moorei 



Family Atyid^. 

 Caridiua nilotica 



var. gracilipes ... ^ P P P P 



Limiiocaridina retiarius Gen. E 



„ parvula E 



tangaiiyikae ... E 



„ similis E 



„ latipes E 



„ socius E 



„ spinipes E 



Liranocavidella alberti ... ... ... Gen. E 



Caridella cunningtoni Gen, E 



,, minuta E 



Atyella brevirostris Gen. E 



„ longirostris E 



6 genera 3E, IP. IP. IP. IE, IP. IP. 



14 species 12 E. IP. IP. IE, IP. IP. 



Otber parts ot 

 the world. 



Asia, Australia. 



The adjoining table shows at a glnnce the most striking 

 feature of distribution, namely thf\t while Caridina nilotica var. 

 gracilipes t occurs in nearly all the big lakes of Africa, it is not 

 found in Tanganyika, but is replaced there by 12 endemic species 

 belonging for th.e most part to endemic genera. Lake Albert 

 also contains an interesting endemic form (obtained by the 

 German Central Africa Expedition and described by Lenz 

 (109, p. 132) and Bouvier (52, p. 575)) in a(hlition to the above- 

 mentioned widely distributed Caridina, while Kivu is the only 

 lake of those at present under review in which prawns have not 

 hitherto been observed. 



The first species of prawn ever taken in the African lakes was 



t A detailed account of the Macrara of the Third Tanganyika Expedition is given 

 b}^ Caiman (61), and forms the principal source of information on this grou]). 



* The species of prawn collected b}- Schubotz at Kassenje on Lake Albert was 

 described by Lenz (109, p. 130) as Caridina longirostris Milne-Edwards. It is, 

 however, coramonl}^ agreed that longirostris is identical with the earlier nilotica, 

 so that, apart from the varietal name, this is the same form that occurs so widely 

 distributed in Africa. Since the type described as Caridina nilotica var. gracilipes 

 is certainly rather variable, it seems probable that the Lake All)ert specimens are not 

 sufficiently distinct to be recorded under a different name, and this is the view which 

 I have taken in compiling the table of distribution above. For a discussion of these 

 questions of synonymy consult the paper of Caiman (61, p. 189 et seq.) and the 

 subsequent paper of de Man (110), which arrives at somewhat different conclusions. 



X I adopt the vai-ietal identifications of Hilgendorf (100), Caiman (61). and Lenz 

 (109), but it is only right to point out that de Man (110) takes a dift'erent view. 

 He appears to consider that the form occurring in Lake Victoria is to be referred to 

 the typical Caridina nilotica itself, and the form from Nyasa to his newly estab- 

 lishod variety natal ensis . The t3'pe Caridina nilotica var. gracilipes he records 

 oiil}^ from the islands of Celebes and Salayer in the Malay Archipelago. 



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