Miscellaneous. 341 



Fischer; C. viridis, Fischer: and C. serralatus, Fischer. In the 

 same region lies the Laugarvatn Lake, from which sulphurous 

 thermal springs arise. Here M. llabot captured, at a spot where 

 the water attained the temperature of 19° C. : Sida cnjsUdlina, 

 ().-F. Miiller ; Macrothnx sp. ? ; Ahma affinis, Leydig ; Eunjrercns 

 lamdlatua, O.-F. iliiller ; PleuvoAnis nanus, Baird ; Cyclops viridis, 

 Fischer ; C. serndaiKs, Fischer ; C. Jimhriatns, Fischer ; and Can- 

 ihocamptus sp. ? With the living specimens there was obtained in 

 the neighbourhood of the mineral and Avarm springs a very large 

 (juantity of remains of the same Entomostraca, whence we may 

 conclude that the animals live only at a certain distance from these 

 springs ; their existence is menaced as soon tw they approach them 

 for any reason whatever. 



Holo/jedium gihberum, Zaddach, which it is extremely interesting 

 to meet with in Iceland, was found only at the most devated point 

 of the plateau which separates the Seydisfjord from nie Lagarflijot 

 (eastern region), in a pool a few centimetres deep, with a sandy 

 bottom and bordered with marsh-plants. This Cladoceron was 

 hitherto considered as one of the most characteristic forms of the 

 pelagic region of the great lakes. Moreover it occurs, in the case 

 in question, in company with Diaptomus minutus, Lilljeborg, and a 

 variety of Cijdops strenuus, Fischer, both species and variety having 

 a pelagic facies. In the same pool, in which the temperature of 

 the water was 9° C, Diaptomus (/lacialis, Lilljeborg, was also very 

 abundant. An analogous condition of things is exhibited by a sheet 

 of peaty water in the valley of the Lagarfljot ; here we find asso- 

 ciated together Bosmina arctica, Diaptomus minvfus, and D. f/Iacialis, 

 with the variety of Cijdops strenuus mentioned above, in addition 

 to certain pelagic llotifera, Asplanchna helvetica^ Imhof, and Anurea 

 sp. ?, for example, and a Protozoon, Ceratium longicorne, Perty, not 

 to speak of several common littoral forms which have already been 

 enumerated. 



In accordance with our directions M. Eabot did not fail to search 

 for specimens with a very small net in the puddles of water only 

 1 or 2 centim. deep and 7 or 8 centim. broad, situated on the cone 

 of the great geyser ; but nothing alive was obtained there. As for 

 the other geysers, their waters flow rapidly away towards the Hvita 

 without forming any pools. 



The most remarkable general fact concerning the fauna of the 

 fresh waters of Iceland is unquestionably the mixture of the Ento- 

 mostraca of the arctic with those of the temperate zone. Within 

 the high latitudes in the Commander Archipelago (Behring Straits) 

 and in Greenland there occurs, among other forms, Eurycercus 

 ylacialis, Lilljeborg. We might expect to meet with this Cladoceron 

 in Iceland ; nevertheless it is not found. Everywhere, in the east 

 as in the west of the island, it is the common E. lamellatus, O.-F. 

 Miiller, so widely distributed in Europe, that constantly appears. 

 On the other hand, characteristic arctic species, such as Bosmina 

 arctica, Diaptomus minntus, and D. r/Iacialis, arc very common in 

 Iceland. The only localities hitherto known for the two Calanidic 



