408 Prof. M'Intosh on the 



Ascidians stud the blades of the Fuci and tangles at low 

 water, wliile very large species grow in the quiet parts of the 

 inland seas. Other interestins: forms are Clavelina^ Cynthia 

 echinata^ C. (Forbesella) tessellafa, and Molgula. Moreover, 

 the surrounding seas occasionally swarm with Salpee, both 

 solitary and in tlie remarkable chains. So far as known no 

 Salpas have hitherto been found on the north-eastern shores, 

 and such, at any rate, like the occurrence of the Physophores, 

 must be very rare. In the offshore waters of the west Dolio- 

 lum is now and then captured, and thus the west and the 

 south agree in this respect. 



In the department of fishes the contrast is sufficiently 

 marked. Thus in the loch salmon and salmon-trout fre- 

 quently leap above the surface close inshore. Young wrasses 

 swim in shoals at the margin of the rocks, or lurk under the 

 sea-weeds of the rock-pools. Biraaculated suckers are 

 prevalent in the Laminarian region, and green cod and conger 

 are more abundant than on the east. 



Of the marine mammals seals are much more numerous 

 than on the east, the headquarters of this species being in 

 the Sound of Harris. A few great grey seals haunt the rocks 

 at Hashkeir. Finners and porpoises are likewise more 

 frequently observed, and the same may be said of the killer 

 [Orca). 



When we come to the extreme nortli of Scotland, viz., the 

 Shetland Islands, we encounter a very rich marine fauna — 

 not so much between tide-marks as in the voes and in the 

 deep water beyond. 



A wealth of large sponges, including perhaps the "grandest " 

 British sponge {Phakellia ventilabrum) , is diagnostic. Besides 

 the foregoing another cup-sponge [Isodyctia infundihullformis) 

 is common, and this region is also the home of the remarkable 

 turnip-sponge [Oceanapia Jeffreysii, Bow.), with branched 

 processes of considerable length growing from both poles of 

 the sphere, while the interior, into which those fistulas pass, 

 is filled with sarcode, to the extent, as its discoverer, Canon 

 Norman, says, of nearly a pint. The interesting Geodia 

 zetJandica and the yellow sea-apple [Tethea cranium) are 

 also present. 



Of the Coelenterates between tide-marks the abundance of 

 Coryne pusilla and Gonothyrcea, and of Tuhidaria indivisa 

 with T. larynx parasitic on it at low water, merit notice, 

 both of the latter being characteristic of the deeper water in 

 the east and west. Between tide-marks also the anemones 

 Actinoloha dianthus and Corynactis viridis are found; while 

 Gorymorpha occurs in the sandy voes. Moreover, in tlie 

 latter and in the sounds in July immense numbers of a 



