50 Messrs. Brady and Robertson on the 



A glance, however, at the table appended to this paper will 

 at once show that our knowledge of the Ostracoda of some 

 parts of the British seas is as yet very scanty, and that there 

 are in fact only a few districts (columns 4, 7, 8, 9) which have 

 been examined with tolerable completeness. Much may still 

 be done even in these better-explored provinces, while the 

 freshwater inhabitants of most districts are at present entirely 

 untouched. 



1. The Freshwater Lakes of Mayo and Galway. 



Of the almost innumerable lakes scattered through these two 

 counties we have at different times more or less thoroughly 

 examined twenty of the most accessible, namely those lying- 

 near the roadside between Galway and Clifden, and others 

 within easy reach of the towns of Roundstone, Clifden, and 

 Westport, The names of these (according to the Ordnance 

 maps) we give as nearly as possible in their natural order, 

 beginning with the most southerly : — Lough Aubwee, L. Corrib 

 (at Oughterard), L. Agraifard, Park Lough (Derryneen), L. 

 Shindilla, Loughaughnarhin, L. Ardderry, Ballinahinch L., 

 L. Nascrahoge, L. Cam, L. Naweelaun, L. Bollard, L. Fadda, 

 L. Doolagh, Seaville L., CregdutF L., L. Enask, L. Inagh, 

 L. Moher, Coolbarreen L. 



These lakes are uniformly of a character unfavourable to a 

 great abundance of Entomostraca or any form of animal life, 

 the bottoms being either stony or composed of a tough com- 

 pact peat which does not easily disintegrate, and thus would 

 appear to supply very scantily either food or shelter. Floating 

 aquatic weeds, such as My7'ioj)liyUum and Potamogeton, occur 

 also very sparingly ; and though sedges and water-lilies are 

 in some lakes plentiful enough, we have never found these 

 very productive in Ostracoda. The following list embraces 

 all the species taken by us ; and not one of these occurred in 

 any great abundance : — 



Cypris laevis, Miiller. 



ovum {Jurine). 



compressa, Baird. 



striolata, Brady. 



(?)tessellata, Fischer. 



reptans (Baird). 



Cypridopsis vidua {Miiller). 



obesa, B. 8i- R. 



villosa {Jurine). 



Candona Candida {Miiller) . 



lactea, Baird. 



diaphaua, B. 8f It. 



Kingsleii, B. ^ B. 



Notodronias monachus (Miiller). 

 Metacypris cordata, B. ^ R. 

 Limnicy there Sancti Patricii, B.^-R. 

 Loxocouclia elliptica, Brady. 

 Darwinella* Stevensoni, B. 8c R. 



* The generic name Polycheles, under which we originally described 

 this species, being preoccupied, we now propose in its place the term 

 Darwinella. 



