76 NOTES AND MEMORANDA. 



Among the foes of slirimps, wliich seem to include nearly every 

 animal in the sea, I am not aware tliat tlie common prawn lias ever 

 been recorded. Where a tub full of shrimps has been emptied into 

 a tank for food, the prawns collect round the spot, and seize and 

 devour at leisure live shrimps, despite their struggles. It would 

 hardly be anticipated that the prawn would prove so deadly an 

 enemy to an animal which seems almost as swift and as strong as 

 itself. Shrimps are almost the only animals eaten alive in the 

 tanks ; very few of the creatures even attack each other. 



The commonest Plymouth star-fish, Asterias glacialis, was ob- 

 served to eat, not only the Mollusca supposed to form its chief food, 

 but also Asterina gibhosa (Aquarium and Wembury Bay), Echinus 

 miliaris (Aquarium), and small Crustacea such as Porcellana platy- 

 cheles and Fortunes, sp. (Wembury Bay) ; the latter were some- 

 times found reddened as if boiled, apparently by the action of the 

 digestive juices. In all these cases the stomach was more or less 

 everted round the food. 



Like the oyster, Pecten maximus, when surprised, can punish an 

 invader by nipping him tightly between its valves till he dies ; an 

 inti'usive Conner {Ctenolahrus rupestris) was caught in this way 

 by the head in the aquarium, and in the morning was dead. 



Gr. H. FOWLEE. 



2. Grayling and Loch Leven Trout in Salt Water. — Some time ago I 

 received a consignment of the above-mentioned Salmonidae from 

 O. Greig, Esq., who has recently built large fish-ponds at Holds- 

 worthy, N. Devon. The fish were all young, averaging about 4^ 

 inches in length ; they were transported in a conical tank of the 

 Howietown pattern, and arrived, with one exception, in a perfectly 

 healthy condition. 



One grayling and one trout were first of all taken, and, as an 

 extreme experiment, transferred to pure salt water. They imme- 

 diately darted off with great rapidity, swimming now round the tank, 

 now with sudden zig-zag bounds after the manner of Mysidae. If 

 at any time they came to rest they floated quickly to the surface, 

 owing to their bodies being unaccustomed to so dense a surrounding 

 medium. 



Their breathing can only be described as violent spitting, and a 

 slight quiver of the body was occasionally noticeable. Both fish 

 soon showed signs of sickening, their motions becoming slower, and 

 their power of keeping below the surface in a normal position less. 

 In about two hours the grayling died, but the trout, with greater 

 tenacity to life, remained alive for four hours. 



The rest of the fish were put into water only slightly salt, and 



