MARINE BIOLOGICAL STATION AT PORT ERIN. 



103 



the sea on to the land in great quantity. On several 

 occasions during the last ten years these swarms have 

 ascended the concrete walls and steps from the beach, and 

 have invaded the old Biological Station in great 

 numbers, hopping over the floor and climbing the walls, 

 so as to get on to tables and shelves. 



/ Orchesha littorea 2 Corophwm gross i pes 

 3 Caprella linearis 



Fig. XIII., Amphipoda (enlarged 5 times). 



The Isopods, unlike the Amphipods, have for the 

 most part broader and flatter bodies (fig. XIV.), are 

 depressed from above downwards, have the legs shorter 

 and less conspicuous, and run or creep in place of leaping. 

 The tail legs which were used for leaping in the Amphi- 

 pods are in part breathing organs in the Isopods, and 



