THE LIFE OF THE SEA-SHORE. 145 
the currents to new localities. In order that new and 
favourable localities may be reached, nature seems willing 
to sacrifice thousands of larve, if perchance a few may be 
saved, Further, that the favouring locality may be 
utilised to the full, not a few of the purely sedentary 
forms have two modes of reproduction. They bud freely, 
the buds remaining attached to the parent or in the 
immediate vicinity. They also produce active larve which 
may insure the distribution of the species to fresh fields 
and pastures new. 
To sum up, the purely littoral forms are sedentary in 
their habits, and have usually means of protection against 
the force of the breakers and the risk of drying up. Almost 
all have free-swimming minute larve, and many in addition 
possess the power of budding. These forms live in 
situations where they are exposed to the atmosphere for 
several hours daily. They are often very tolerant of fresh 
water, and are of great interest from the point of view of 
the evolutionist, because it is probable that from such forms 
both fresh water and terrestrial animals originated. 
2. The second set of shore animals includes those which 
rarely, if ever, leave the water of their own accord, which 
have considerable powers of locomotion, and which are 
to be found in the nooks and crannies of the rock pools. 
As examples of these I shall take chiefly some of the 
common shore fish and the common crustacea. The 
crustacea, and especially the larger forms, are usually 
beautiful in colour and interesting in both their ways 
and their structure. The more specialised forms may 
be divided into two sets—those like the lobster, which 
have a long tail used in swimming; and the crabs, where 
the tail is very short. It may perhaps be said that the 
erabs have no tail at all, but if you examine a common 
crab closely you will find that it has a short tail which 
is carried permanently bent inwards. Now part of the 
interest of our shore crustacea is that not only are there 
true long-tailed forms like prawns and lobsters, and 
true short-tailed forms like the crabs, but there are 
numerous forms intermediate between the two. Take 
first the prawns; they are not common on the shore, 
