A Synopsis of the Recent British Ostracoda. 117 



virens (Jurine), obligua, Brady;* elliptica, Baird; punctillata, 

 Norman ; bispinosa, Lucas ; gibbosa, Baird ; tessellata, Fischer ; 

 clavata, Baird ; salina, Brady ; gibba, Ramdohr ; trigonella, 

 Brady; reptans (Baird); serrata (Norman) , compressa, Baird ; 

 striolata, Brady; ovum (Jurine), Icevis, Miiller; cinerea, Brady; 

 Joanna, Baird. 



Most of the species of the genus Cypris, being enabled to 

 swim freely by means of the setose appendages of the an- 

 tennee, are active in their habits, and very abundant in ponds 

 and small pieces of water, especially where there is much 

 decomposing vegetable matter. They do not appear to be so 

 numerous in large clear lakes, and from elevated mountain tarns 

 they are frequently altogether absent. Some species, however, 

 have their lower antennas very sparingly armed with setae, 

 and those so short and few as to give little or no swimming 

 power. Species possessing such characters (G. reptans and 

 serrata) have been placed by authors in the genus Candona ; 

 but it seems best to restrict that genus, as will be presently 

 mentioned. There is considerable diversity in the colour and 

 external appearance of the Oyprides : some being perfectly 

 smooth ; others simply punctate or striated ; others densely 

 hairy; while one species (tessellata) is most beautifully reti- 

 culated with a pattern which has much the appearance, in fine 

 examples, of silver filagree work. The prevailing colours are 

 uniform shades of brown and green; but some species, as 

 salina and serrata, are variegated with dark markings upon a 

 light ground. Four of the species mentioned above (elliptica, 

 gibbosa, clavata, Joanna) have not been found, or at any rate 

 have not been recognized, since their publication by Dr. Baird ; 

 and one, the finest of all (bispinosa), is claimed as British only 

 on account of its occurrence in the island of Guernsey. It was 

 originally found in Algiers. Perhaps the most abnormal 

 species is G. gibba — an animal which, though its antennae 

 seem well adapted for swimming, apparently never uses them 

 for that purpose, but contents itself with an inactive life upon 

 clayey bottoms, with which its colour closely assimilates. Its 

 shell is much more dense than is usual in this genus, and may 

 perhaps need more power to sustain it in the water than the 

 antennas are able to afford. 



Cypbidopsis, nov. gen. — Like Cypris, except that the 

 post-abdominal rami (Fig. 3) are quite rudimentary, consisting 

 of two slender, setiform processes, springing from a common 

 base. Lives in fresh water. 



G. vidua (Miiller), aculeata (Lilljeborg), villosa (Jurine). — 



* The species to which my own name is attached, are quoted chiefly from a 

 " Monograph of the Eecent British Ostracoda," read before the Linna^an Society, 

 and which will be published in the Transactions of that body. 



