On cautiously approaching a deep rock pool one may often see a lobster rapidly retreat in its usual backward fashion, and snugly house itself in a narrow chink from which it is impossible to remove it. And, when once surprised, it is not likely to show itself again as long as the intruder is in view. If one remains perfectly still for a time, a pair of waving antennæ may be seen gradually protruding from the safe retreat; but, as soon as the stalked eyes have advanced sufficiently to detect the figure of a stranger, the lobster silently withdraws itself till quite out of sight. Lobsters, usually of rather small size, may often be seen quite out of the water at low tide, in the narrow chinks of the rock, or under large stones, but it is no easy matter, as a rule, to get them out. It is of little use poking a stick into the entrance of their hiding-places, though occasionally they will grasp the stick so tenaciously with their forceps that they may be pulled within reach. You _may_ be able to haul them out by their long antennæ, but if you can find a second way into their home such that you can disturb them from behind you are pretty sure of your victim. [Illustration: FIG. 207.--THE SPINY LOBSTER (_Palinurus vulgaris_)] It will be unnecessary to describe other species of lobsters individually, but we have introduced figures of a few for identification. The Norway Lobster (_Nephrops norvegicus_) is often landed in large numbers by the fishermen of the east and south-east coasts and sold at a shilling or so a dozen under the name of Norway Prawns. They are pretty and interesting creatures, and may be easily kept alive in the indoor aquarium, where they may be fed on any kind of fish. [Illustration: FIG. 208.--THE NORWAY LOBSTER (_Nephrops norvegicus_)] Fig. 209 represents the two allied creatures that may sometimes be dug out of the sandy beach, or from the mud in the estuary of a river. The one on the left is the mud-borer (_Gebia stellata_), which is of a dull yellowish colour, marked more or less distinctly by pinkish starlike spots--a feature that has suggested the specific name. The beak in front of the carapace is very prominent and spiny, and the long abdomen is narrower in front than in the middle. This creature hides in the holes that have been excavated by boring molluscs, and seems also to extend the cavities it inhabits by its own labours. The other is very similar in general form, but has no spiny beak and the abdomen is much broader in the middle than at the base. It is also to be distinguished by the very unequal size of its front legs, one of which is much more developed than the other.