132 DP, PS BEDFORD [AUGUST 
locally common; he might also see large Holothurians basking in the sun, 
either stationary or crawling slowly over the mud, but the commonest 
groups would be those that he was already accustomed to. Hermit- 
crabs abound everywhere, and at night the shore will sometimes be 
almost covered with them; crabs and prawns shelter themselves in 
crevices or under stones or in the sand, and Spatangids, Chaetopods, 
and Gephyreans make their burrows in the sand or rocks ; limpets, 
too, of a diminutive size it is true, but still obvious limpets, stick to 
the rocks with the same tenacious grip as elsewhere, and obviously 
fill the same place in the economy of nature ; our common littoral Gas- 
teropod genera, such as Nassa, Purpura, Littorina, Trochus, etc., are 
represented by forms closely similar both in form and habits, and 
many of the species seem to have extremely variable coloration as on 
our own coasts; in fact it would be difficult to name any characteristic 
difference. Polychaet tabes project from the surface on nearly every 
sand-flat, Lamellibranchs abound in the mud and bore into rocks and 
wooden landing-stages, Nudibranchs of brilliant colours, together with 
Polyclads, creep about on stones and sea-weed, and even the abundant 
Periophthalmus which forms so marked a feature of the littoral fauna 
as it bounds over the surface of the pools, or rests on some adjacent 
object just above the water, is after all only a goby, such as every boy- 
naturalist delights to hunt at home. 
The conclusion thus seems forced on our attention that the broad 
features of marine life, the modes of adaptation of different groups to 
their inorganic environment, and the modes of life adopted in their 
mutual rivalries of offence and defence, are to a very considerable extent 
independent of geographical position or climatic influence, and what is 
perhaps more surprising, they would seem to be independent of the 
marked differences which undoubtedly exist among the higher verte- 
brates. The presence of numerous kinds of tropical sea-birds, of sea- 
snakes, of crocodiles, and of a host of curious fish seems to have made 
a scarcely appreciable impression on the habits of the lower forms: 
and from what we know of fossil fauna, commencing from the Olenellus 
and other faunas of the earliest fossiliferous rocks which have retained 
the imperfect relics of but a few of their once living inhabitants, it 
might be surmised that from that time onwards these same broad 
features have persisted all the world over, altered but slightly from 
time to time by the subsequent evolution from some of them of the 
Decapod Crustacea, Vertebrates, and other “higher” forms. No 
doubt, too, in a similar way the exclusively tropical forms, among 
which we may perhaps regard the reef-building corals as in this respect 
the most important, have led to modification of the animals dependent 
on them, but from a superficial point of view at least, the crabs, prawns, 
Cirripedes, Lamellibranchs, and Holothurians that live associated with 
them do not differ very considerably from their allies which are 
surrounded by other environments. 
