106 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



sometimes green, yellow and purple lines. It is only 

 after death that the prawns become opaque, and more or 

 less red in colour. Shrimps are not so transparent when 

 alive, and do not become so red when boiled. They are 

 grey, and are usually speckled and mottled with black 

 and white so as to be very much of the same appearance 

 as the sand in which they live. As the figure shows, the 

 prawn has more of a hump on its back than the shrimp, 

 and can be easily distinguished by the long spiny snout 

 or " rostrum " between the eyes. There are many other 

 differences, and it must also be remembered that we have 

 several kinds of shrimps and several different kinds of 

 prawns in our seas. 



The lobster (Homarus vulgaris) is one of the most 

 familiar of the higher Crustacea, and scarcely needs 

 description. Its appearance when living in our tanks 

 differs remarkably, however, from that of the almost 

 lifeless animal so often seen on the fishmonger's slab. 

 When placed in a tank its first care is to select a con- 

 venient hiding place amongst the large stones. This it 

 does by means, in the first place, of its long antenna? or 

 feelers, which are waved about in any likely hole or 

 crevice, and, should this preliminary examination be 

 satisfactory, the great claws are then inserted. When 

 assured that no enemy lurks within, the lobster takes 

 possession by turning and backing quickly into the hole. 

 Once comfortably lodged, it lies almost motionless in its 

 house, with the tips of the great claws close together at 

 the entrance, the long feelers waving very slowly to and 

 fro outside, while the antennules or short feelers are 

 frequently and sharply jerked in much the same way 

 as a driver uses his whip. A would-be intruder is 

 promptly attacked and driven off, and these encounters 

 with other lobsters occasionally result in the loss of one 



