97 



in which to bury themselves, when nothing can be seen of them 

 but their tentacula ; ten beautiful purple tufts radiating from a 

 centre and occupying a circle of six inches in diameter. This 

 species, with the other Holothurise, Psolus, Cuvieria, &c. adhere 

 so strongly by their suckers that their disks are left upon the 

 rock when they are torn away. 



It would be interesting to ascertain what constitutes the com- 

 mon food of such a multitude of animals. I have seen a barren 

 rock of several rods in extent, covered with Echini, upon which 

 no other animal nor any plant could be detected, which might 

 serve them for food. 1 should mention, that when a fish is killed 

 by the fishermen and thrown into the water, it becomes covered 

 with the Echini, who soon devour it. 



The pebbly shores are also covered with Mytili, the larger 

 boulders being encased with Patellse, {AcmcEa testudinalis,) 

 and below with a large species of Ascidia. Of the free swim- 

 ming animals, the Medusae, chiefly Staurophora laciniata^ Kg. 

 are sometimes met with in such crowds that the passage of a 

 boat through them is obstructed. The waters are also filled 

 with Crustaceans, of which a shrimp, the Mysis Fahricii, is the 

 most abundant. These form the food of the herring and pol- 

 lack, which visit the shores in large shoals at this season. 



The first visit of an observer to the shore at low tide would 

 lead him to form an opinion that the number of species inhabit- 

 ing the region must be very great, since two or three hundred, of 

 different classes, might be obtained during a single retreat of the 

 tide. But a second visit, and dredging operations, soon correct 

 this view ; for although the same species present themselves in 

 increased abundance, the number of additional species obtained 

 is very few. In fact, the region presents the true characteristic 

 of a northern climate ; the number of species being small, while 

 the number of individuals is very great. 



The naturalist will not fail to be struck with the facts which 

 present themselves concerning the depths at which the species 

 live. It is surprising to find species which we have always 

 regarded as inhabitants of very deep water, living at very slight 

 depths or even above low water mark. Many remarkable in- 

 stances of this might be mentioned. The Terebratula, a mol- 

 lusk of the class Brachiopoda, which is always referred to as 



PROCEEDINGS B. S. N, H, 7 DECEMBER, I80I 



