278 Mr. ^Y. F. de Visraes Kane on 



some risk reached the dredging-gvounds, and couhi 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 plienomenon 

 of the existence of these blind Crustacea, usually inhabitants 

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

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

 that the two lakes liave underground communications. 

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

 the latter, which off' 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 rclicta rewarded my efforts, 

 but not a single JSiphargiis. These deeper soundings reached 

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

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

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

 fying, were exactly the reverse of my expectations. Searching 

 lor My sis in Lough Mask, I took JSiphargus Kochianiis, and 

 following up wiiat I thought to be its probable extension to 

 Lough Corrib, I met with Mysis reWcta, 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 Lake of Zirknitz presenting little room 

 for doubt. A similar explanation for the presence of iVz'- 

 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 

 Assures has, in the course of ages, dissolved tlie softer strata 

 and formed underground channels and reservoirs, sometimes 

 of great extent and miles in length. Miuiy such subterranean 

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

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



