376 EEV. A. M. N0BMAN AND MB. G. S. BEADY 



neque truncatum, unguibus terminalibus parvis, orificio genitali 

 externo ante eosdem ad apicem abdominis sito." 



Lynceus elongatus is common in elevated lakes and moorland 

 tarns in Great Britain and Ireland. We bave fonnd it in almost 

 all sucb localities tbat we bave examined in tbe counties of Dur- 

 bam, Northumberland, Cumberland, Westmorland, Dumfriesshire, 

 Kirkcudbrightshire, Bosshire, and also in Lewis and Connemara ; 

 but it appears to be of comparatively rare occurrence in lowland 

 situations. On tbe Continent it is known to inbabit Prussia and 

 Norway. 



Lynceus striatus of Jurine appears to us to represent tbis species 

 ratber than tbe Acroperus liarpa of Baird. 



4. Lynceus tenuicatjdis, (G. 0. Sars.) PI. XIX, fig. 3. 



1858. Camptocercus alonoides, Scboedler. Die Brancbiopoden 

 der Umgegend von Berlin, 1 Beitrage, p. 27 {only name, 

 no description). 



1862. Alona tenuicaudis, G. 0. Sars. Om de i Omeg. af Christ. 



forkom. Clad. Andet Bidrag., p. 37. 



1863. Alona camptocercoides, Schoedler. Neue Beitrage der 



Xaturgeschichte der Cladoceren, p. 24. PI. I, figs. 

 8-10. 



Carapace subquadrangular, not short ; dorsal margin well 

 arched from the extremity of the rostrum to the supero-posteal 

 angle ; ventral margin nearly straight, ciliated ; posterior margin 

 truncate, with the infero-posteal angle well rounded and not 

 furnished with any tooth ; surface longitudinally striated, and 

 when alive and highly magnified a few minute punctures are 

 seen between the striee. Head smaller and more depressed than 

 in L. quadmnyularis, rostrum blunt, hood-formed. Eye large, 

 and the accompanying eye-spot more than half its size, situated 

 midway betAveen the eye ' and the extremity of the rostrum. 

 Abdomen long, narrow, and parallel-sided, angular process mi- 

 nute, supero-posteal angle slightly produced but rounded off, 

 abdominal spines, from eighteen to twenty, very minute, except 



