362 Messrs. Brady and Robertson on Dredging 



OSTRACODA. 



Lists of Species taken. 



Mullingar Canal, Dublin. 



Cypris compressa, Baird. 



reptans {Baird). 



Cypridopsis obesa, nov. sp. 

 Candona Candida (Midler). 



compressa (Koch). 



albicans, Brady. 



Limnicytbere inopinata (Baird). 



River Liffey, at Dublin, North Wall. 



Candona compressa (?) (Koch). 

 Bairdia fulva, Brady. 

 Cytbere lutea, Midler. 



castanea, G. O. Sars. 



Cytheridea elongata, Brady. 

 Loxoconcba impressa (Baird). 



elliptica, Brady. 



Oytberura nigrescens (Baird). 



similis, G. O. Sars. 



cellulosa (Norman). 



cuneata, Brady. 



Paradoxostoma variabile (Baird). 



Westport Quay, in a salt-tvater tidal 

 pond at high-water mark, amongst 



Zostera. 



Cytbere lutea, Midler. 



castanea, G. O. Sars. 



villosa, G. O. Sars. 



cicatricosa, G. O. Sars. 



gibbosa, nov. sp. 



Loxoconcba elliptica, Brady. 



Xestoleberis aurantia (Baird). 



Cytberura nigrescens (Baird). 



Robertsoni, Brady. 



Sclerochilus gracilis, nov. sp. 



Lough Moher, Mayo. 



Cypris ovum, Jurine. 

 Limnicytbere Sancti-Patricii, n. 



sp. 



Freshwater Loughs near Clifden. 



Cypris laevis, Midler. 

 Loxoconcba elliptica, Brady. 



Respecting the marine species, it should first be noted that 

 all our dredgings being made in comparatively shallow water, 

 many species are absent from the list which would doubtless 

 have appeared had our time admitted of dredging in greater 

 depths. Yet the results obtained are interesting, as indicating 

 some well-marked peculiarities in the fauna of our Atlantic 

 shores. Most remarkable, perhaps, is the almost entire ab- 

 sence of Cythere lutea y a species which in all other parts of the 

 British islands is one of the most abundant. Cythere tubercu- 

 lata and concinna appear also to be excessively scarce ; and the 

 strongly spinous species, such as C. antiquata and Jonesit : 

 become much less robust, with more fragile shells and fewer 

 and more attenuated spines. Cytlieridea punctillata, a spe- 

 cies veiy abundant in some of the Scottish lochs, as well as in 

 most glacial clays, is also absent : the same may be said of 

 Ilyobates bartonensis and Cythere dunelmensis. The common 

 Cytheropteron latissimum appears to be displaced by C. nodo- 

 sum. The occurrence of Loxoconcha elliptica in the freshwater 

 lakes has already been noticed in our introductory remarks. 

 The species which seem to be most characteristic of the district 

 are perhaps Cythere Macallana, pulchella, and cicatricosa, 

 Cytlieropteron nodosum and C. subcircinatum. All these have 

 indeed been found on other parts of the British coast, but no- 

 where so abundantly as in these dredgings from the bays of 



