138 History of British Entomostraca. 



proaches near to Cypris crassa, Muller, in his description of that 

 species, but differs in toto from the figure which he gives of it. 



A species of fossil Cypris occurs in the limestone of Burdiehouse 

 quarry, near Edinburgh, but which I have not had opportunities of 

 sufficiently examining. 



2d Genus, Cythere. 

 Bibliographical History — Otho Fridericus Muller is the first na- 

 turalist that has taken notice of this genus of insects. Before his 

 time they were perfectly unknown, not the slightest mention of 

 their existence having been made by any previous writer. As it is 

 to him that we are indebted for the first information, so it is to him 

 alone that we owe all that we do know, with the exception, I be- 

 lieve, of what few additional particulars will be found in the follow- 

 ing pages. Upon a slight inspection, the Cytheres might be mis- 

 taken for Cyprides ; but their antennse being simple, and free from 

 the pencil of long hairs with which these organs in the Cypris are 

 endowed ; their possessing eight feet ; the want of the long tail, and 

 their inhabiting salt water, sufficiently distinguish the two genera. 

 It is in his " Entomostraca" that Muller first established this genus, 

 and the above marks of distinction between it and the Cypris, con- 

 stitute almost all the knowledge that he imparts to us concerning 

 it. Meager as it is in details, it has not been enlarged by any suc- 

 ceeding author. Gmelin, in the " Systema Naturae," 1788 ; Fabri- 

 cius in his " Entomologia Systematica," 1793 ; Manuel in the " En- 

 cyclopedie Methodique," 1792 ; and Latreille in his " Hist. Nat. 

 Gen. et Part, des Crustaces," &c. 1802 ; either merely give the spe- 

 cies alone, or repeat the few remarks made by Muller, without mak- 

 ing any comment or original observations of their own. Lamarck, 

 in his " Hist. Nat. des Animaux sans Vertebres," 1818, changes 

 Muller's name, and gives the genus the appellation of Cytherina ; 

 while Desmarest, in his " Consid. Gen. sur les Crustaces," 1825, in 

 repeating the observations made by Muller, and giving merely his 

 species, adds, that it may turn out that some of the eight feet may 

 be particular organs, and that the number of true feet may be found 

 to be the same as in the Cypris, a conjecture which Latreille also 

 makes in the last edition of " Cuvier's Regne Animal," 1829. Des- 

 marest moreover says, " reasoning from analogy, there is reason to 

 believe that the Cytheres like the Cyprides have their branchial 

 plates attached to the mandibles and jaws, and that their feet are 



