150 THE HON. PAUL A. METHUEN ON [Feb. 1, 



occur ; in the family Apodidse, Apus alone is represented ; among 

 the Copepods we find rather a striking fauna : Boeckella is 

 absent, and we find instead several genera some of which appear 

 to be peculiar to South Africa ; Crayfishes are absent from the 

 spruits and rivers, the chief occupants appearing to be the river 

 crabs and prawns. Of further interest is the great resemblance 

 some of the forms found in the Transvaal bear to their European 

 representatives ; in all cases where possible, their points of 

 resemblance to particular European forms have been mentioned ; 

 it is also interesting that Daphnia pulex, which was found 

 in a clam near Pretoria, is in nearly every detail similar to the 

 Daphnia pulex of European waters (vide PI. XV. fig. 40). 



But to return for a moment to the Copepods. Including the 

 Metadiaptomus of this paper, in all, four genera peculiar to South 

 Africa have been determined. Of these the dominant genus 

 Broteas ( = Lovenula) appears to be the most widely distributed. 

 Moreover, several species of Diaptomus have been described from 

 South Africa, notably by Mrazek (6) from German West Africa. 

 The genus Metadiaptomus resembles Adiaptomits, described by 

 A. W. Cooper (2), in that the antennule possesses twenty-six 

 segments instead of twenty-five as in Diaptomus ; but a glance 

 at PI. XVI. fig. 46 a, and PI. XVIII. fig. 55, will show two 

 further peculiarities : (1) in that the antennal region of the thorax 

 appears to be distinctly divided from the rest of the body ; and 

 (2) in the marked difference in the structure of the modified 

 sixth pair of thoracic appendages from that of Diaptomus, 

 especially in the male (vide text-fig. 116, p. 162). 



Summing up the question of distribution here discussed, it 

 might be said briefly : (1) that the Entomostraca here described 

 show no relation whatever to Crustacea from the Bassian Region 

 of Australia : (2) that they do show a certain approach, in some 

 cases a marked resemblance, to European forms ; (3) that, further, 

 they have been evolved to a certain extent along lines of their 

 own, showing considerable modifications which are not paralleled 

 elsewhere. 



In conclusion I take this as an opportunity of expressing my 

 gratitude to Dr. Gunning, of the Transvaal Museum, for his kind 

 assistance and advice ; and to Mr. G. W. Smith, who just before 

 I left England suggested Lake Chrissie as likely to yield some 

 interesting results, for the help and encouragement he has given 

 me in preparing the following descriptions ; and I feel, if there 

 is anything in this paper of interest or value, it is due to his 

 suggestions. 



Older OSTRACODA. 



Family C y p r i d m. 



The classification of G. W. Midler (7) has been adopted for 

 assigning to the Ostracods here described their systematic- 

 position. They are all five undoubtedly Cyprids having eight- 

 segmented antennules which are provided with long and slender 



