278 Mr. "W. F. de Vismes Kane on 



some risk readied the dredging-grounds, and could venture 

 only two short hauls of the dredge, I secured about 130 

 examples at a depth of from 130 to 150 feet, some of which 

 were only about 2 mm. long and of a paler orange than the 

 larger specimens, probably being younger. The phenomenon 

 of the existence of these blind Crustacea, usually inhabitants 

 of subterranean waters, made me desirous of testing tlie adja- 

 cent Lough Corrib also for these animals, as 1 was aware 

 tliat the two lakes have underground communications. 

 Accordingly I spent two days (the 13th and 14th August) on 

 the latter, which oflf Cong, where the outflow of Lough Mask 

 enters it, reaches its deepest soundings, one other area on the 

 western shore some miles away only excepted. I therefore 

 dredged along the shore of the narrow isthmus which divides 

 the two sheets of water, in the bays, and also in moderate 

 depths of 60 to 70 feet bordering the shore, for a distance of 

 about two miles, but without success. I then tested the 

 depths further out in the lake, with the unexpected result 

 that a moderate number of AJysis relicta rewarded my efforts, 

 but not a single JSi'phargus. These deeper sovuidings reached 

 from 110 to 132 feet, and tiie floor of the lake varied from 

 soft mud to a hard gravelly bottom, with occasional stones. 

 The results of my researches, therefore, though highly grati- 

 fying, were exactly the reverse of my ex|)ectations. Searching 

 lor Mysis in Lough Mask, 1 took JSiphargus Kochianus, and 

 following up what 1 thought to be its probable extension to 

 Lough Corrib, I met with Mysis relicta, both of them remark- 

 able captures. 



The question arises as to the origin of this normally 

 subterranean species in the open waters of a lake. Two 

 allied species, as already mentioned, have been described 

 from similar localities on the Continent, and both of them 

 were presumed to have been derived from underground 

 sources, that from the Lakeof Zirknitz presenting little room 

 for doubt. A similar explanation for the presence of iVi*- 

 phargus Kochianus in Lough Mask is available. The 

 northern and eastern shores of this picturesque sheet of 

 water are for the most part flat, with only slight undulations, 

 and consist of horizontal strata of carboniferous limestone, 

 which extend south along Lough Corrib to Galway. As is 

 well known, the rain-water accumulating in its hollows and 

 fissures has, in the course of ages, dissolved the softer strata 

 and formed underground channels and reservoirs, sometimes 

 of great extent and miles in length. Many such subterranean 

 waters find their way into, and others take their rise from, 

 Lough Mask. Its, western shore, however, is of igneous 



