8 THE ENTOMOSTRACA OF 



Liljeborg divides the Cyprince into three genera, characterised as follows 



Eye double. 



Eye single 

 (coalesced). 



Second pair of maxillae with- 

 out branchial appendage. 



Both pairs of maxillee pro- 1 

 vided with branchial ap- 

 pendage. 



Lower pair of antennae 

 provided with a 

 pencil of setae, or 

 filamentous plume. i 



f Setae long, reaching s 



much beyond the I AT , i 



c ^i i • i )INotodrornas. 

 apex or the terminal 



hook. 



Setae reaching as far' 



as or beyond the 



apex of the terminal 



hook. 



Second pair of maxillae with- | Lower pair of antennae) 

 out branchial appendage. ] without a pencil of 



setae. 



Setae short. 



Cypris. 



. Candona. 



The researches of Liljeborg and Zenker often coincide in their results ; but these 

 authors differ widely in their views as to the synonymy of several forms, owing to the 

 often imperfect accounts and figures by earlier naturalists, — to the different extent or 

 direction of the zootomical examinations made by these two authors respectively, — 

 and to the different appreciation of the value of the form of the carapace entertained 

 by them. 



As it is necessary that the anatomy of all the species must be fully and equally well 

 examined previously to a complete classification on anatomical grounds being made, 

 it is evident that any arrangement is incomplete until each known species has been 

 subjected to such a minute examination as that instituted by the crustaceologists 

 above referred to. 



In the meantime palaeontologists must be guided in the recognition of specific 

 forms by the characters of the carapace-valves, which, however, among the Cyprhuz 

 do not present satisfactory generic differences of character. The carapaces of Cypris 

 proper, Cypria, and Notodromas or Cyprois are similar in general structure and form. 

 The carapaces of the Candona, or the group which are destitute of the plume on the 

 lower antennas, for the most part resemble those of Cyprides, but are conspicuous for 

 their great relative size and oblong shape. A distinct hingement, however, is present 

 in a Candona-like species which occurs recent at Gravesend, and fossil in our pleisto- 

 cene deposits. This animal resembles Candona in its plumeless lower antennae ; but 

 minute anatomical examination is required to determine its exact relations. In the 

 meantime, on account of the hinge and the comparative coarseness of the carapace, 

 I shall regard this as a sub-generic form, under the appellation of Cyprideis. 



In the 'Munich Transactions,' of 1855, Dr. S. Fischer has given us an additional 

 memoir on the Ostracoda, in which he refers to some of Zenker's and his own 



1 These short setae do not form & plume, and characterise forms which are inc'nded in Baird's genus 

 Candona. 



