History of British Ento mostraca. 517 
turalists who have written upon this genus ; he only describes the 
Cypris strigata of Muller. M. Daudebart de Ferussac, fils, in a 
memoir published in the " Annales du Museum d'HistoireNaturelle, 
Tom. 7th," 1806, describes a new species ; and M. Risso, in his" His- 
toire Naturelle des Crustaces des Environs de Nice," 1816, describes 
two additional ones ; but though these additions were made to the 
number of known species, and although Latreille, in Cuvier's " Regne 
Animal," 1817, and Lamarck, in his " Hist. Nat. des Animaux sans 
Vertebres," 1818, give a variety of details concerning the genus 
generally, little real knowledge concerning the anatomy of the in- 
habitants of the tiny shells was conveyed to us, as Ramdohr's work 
seems to have attracted no attention, till M. Straus published his 
admirable paper on the genus Cypris in the 7th Vol. of the " Me- 
moires du Museum d'Histoire Naturelle," 1821, containing a most 
elaborate anatomical description of the genus, with a notice and fi- 
gures of three new species not described by Muller. About the 
same period as Straus read his paper before the Academy, appeared 
Jurine's splendid work on the Monoculi, containing many very in- 
teresting details of this genus generally, with beautiful figures of 
18 species ; but both of these authors appear to have been ignorant 
of the previous work of Ramdohr, as we find no reference made by 
either of them to his excellent little work, though published fifteen 
years prior to theirs. Desmarest in his " Considerations Generales 
sur les Crustaces," 1825, although he gives a very good account of 
the different genera,' taken chiefly from Straus and Jurine, with a 
description of 21 species, takes no notice of Ramdohr ; though M. 
Latreille, in the last edition of the " Regne Animal," 1829, notices 
his memoir with all due approbation, and has contributed much to 
make his labours more generally known. We know of no original 
memoir upon this genus having been published in this country, 
though in " Rees' Cyclopedia," under the Art. Monoculus, we have 
the species described as given by Fabricius ; and in Leach's article 
Crustacea in the "Edinburgh Encyclopedia," we have no details, 
and only two or three species taken notice of. 
ANATOMY. Muller, Ramdohr, Jurine and Straus, all differ in 
many respects in describing the anatomy of the genus Cypris, both 
as regards the nomenclature and the use of the parts described by 
them. In minuteness of detail and accuracy of description and 
figures, the memoir of Straus, however, stands pre-eminent amongst 
those of his fellow-labourers, and though in the following remarks 
we shall take all advantage of the memoirs of the other three au- 
thors, we shall follow M. Straus more particularly, in his aomen- 
