408 Prof. M'Intosh on the 



Ascidians stud the blades of the Fuci and tangles at low 

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

 inland seas. Other interesting forms are Clavelina, Cynthia 

 echinata., C. [Forhesella) tessellafa, and Molgula. Moreover, 

 the surrounding seas occasionally swarm with Salpge, both 

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

 Salpte liave 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, ^oung wrasses 

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

 sea- weeds of the rock-pools. Bimaculated 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 north of Scotland, viz., tlie 

 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 ventilahrum) , is diagnostic. Besides 

 the foregoing another c\i\)-s\)Ouge{Isodyctia infundibultformis) 

 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 Tuhularia 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 

 Actinoloba dianthus and Gorynactis viridis are found; while 

 Gorymorpha occurs in the sandy voes. Moreover, in the 

 latter and in the sounds in July immense numbers of a 



