1898J SOME NEW BOOKS 55 



is nowhere mentioned that, in the latter group, papillae occur at all. 

 Fortunately, however, a bibliographical index is given, so that it is 

 not necessary to remain long in doubt as to the facts. 



Cyclops 



Bulletin of the Illinois State Laboratory of Natural History, Urbana, 

 Illinois. Volume v. Article ii. A contribution to a knowledge of North 

 American Fresh- water Cyclopidae. By Ernest B. Forbes, B.S., 1897. 



Anales del Museo Nacional de Buenos Aires. Tomo v., pp. 331-332. Sur 

 quelques Entomostrace's d'eau douce des environs de Buenos Aires. Par Jules 

 Richard, 1897 (Aparecio el 8 de Junio). 



Fifteenth Annual Report of the Fishery Board for Scotland, Part iii. The 

 Invertebrate Fauna of the inland waters of Scotland. Part \\i. By Thomas 

 Scott, F.L.S., Mem. Soc. Zool. de France. Plate ix. 1897. 



Mr Ernest B. Forbes has utilised an academical essay to adjust 

 the synonymy of the fresh-water Cyclopidae of North America. 

 Unfortunately he has to admit that his revision of the group is still 

 incomplete. He institutes two new subgenera. Some people like 

 subgenera ; others regard them as scientific misfortunes. In compen- 

 sation Mr Forbes cancels several species too hastily introduced as 

 new by American writers. These results have evidently not been 

 won without much laborious and conscientious comparison of s^Deci- 

 mens. Whether all Mr Forbes' conclusions are valid it would be 

 premature to decide. At the outset he lays stress on the fact that in 

 the Cyclopidae, " of all the specific characters, the most valuable are 

 those derivable from the rcce'ptacnlum seminis." Then, on the ground 

 of certain microscopic characters, he upholds the Cycloids cdax of his 

 instructor, Dr S. A. Forbes, as a distinct species from Cyclops leuckarti 

 Claus, although he himself says " the structure of the receptaculuvi 

 seminis is identical in the two species, so far as I can tell." But of 

 Cyclo'ps cdax he makes Cyclops annulatus Wierzejski a synomyn. 

 Eather opportunely, therefore, Dr Jules Eichard has just published 

 a figure of the receptaculum seminis in Cyclops annidatus, relying on 

 it as a character distinguishing that species from the neighbouring 

 Cyclops leuckarti. But if the ?*. s. in C. cdax agrees with, and the r. s. 

 in C. annulatus differs from, that in C. leuckarti, it would follow that 

 C. edax and C. annidatiis, cannot be identical, or else that the r. s. 

 does not deserve to have much stress laid upon it. 



The most notable feature separating C. cdax from C. leuckarti 

 is afforded by the hyaline plate of the last joint in the first antennae. 

 In the latter species this has a characteristic notch, not present in 

 the former. Mr Thomas Scott, who has within the last few weeks 

 added C. leuckarti to the known fauna of Scotland, makes a refer- 

 ence to this notch, but speaks of it as a feature of adult specimens, 

 though without definitely stating that it is not found in younger 

 stages. The coincidence of three writers in different parts of the 

 world independently busying themselves with the characters of this 

 little species, of the length of one millimetre, must give an impres- 

 sion that in this age the fauna of the globe is being very carefully 

 scrutinised. 



