54 
Such places are inhabited by various burrowing beetles, especially 
Bledius arenanus a. o. species of this genus, Heterocerus' and Dy- 
schirius. This Bledius-Dyschirius community is especially found on 
the shores of Fanø, but may be met with, more or less developed, 
on all the Danish shores. On tropical shores I have not observed 
anything quite corresponding to this community, though Bledius- 
forms have been found living a burrowing life on sandy seashores. 
The other community of sandy foreshores is characterized as 
the Talitrus-Orchestia-c o m m u n i t y. The forms characterizing it on 
the Danish shores are: Talitrus locusta Pallas, Talorchestia Deshayesi 
Aud. and Orchestia liltorea Mont. All these Crustaceans are mainly 
of nocturnal habit, remaining burrowed in the sand, often 
below washed up algæ or dead animals, during daytime, moving 
freely about on the shore during evening and night. All of them 
are very poor swimmers. Together with these Crustaceans various 
flies occur, e. g. Actora æstuum Meig., Fucellia fucorum, and sev- 
eral species of Chersodromia. They all fly very little, only short 
distances at a time; some of the small Chersodromia's apparently 
cannot fly at all. This, of course, serves to protect them from 
being carried off by the wind. Another fly generally met with on 
the beaches, Scatella æstuans Fail., digs in the sand with its pro¬ 
boscis, in places where constant moisture favours the development 
of a rich microscopical fauna, on which it feeds. — Also the Podu- 
rid, Hypogastrura viatica Tullb. belongs to this community. 
On tropical shores crabs and soldiercrabs are the more con- 
spicuous forms in the corresponding region; also the Isopod Scy- 
phax (observed on New Zealand shores) belongs to this region. 
Within the tidal zone the character of the fauna differs 
very markedly according to the various degree of exposure to the 
action of the waves. In the surf region the Spionid Scole- 
lepis squamata Abildg. is the most characteristic form. It lives 
perpendicularly in the sand, but not in a real tube; when the 
waves retreat, it protrudes its head over the surface of the sand 
and catches all sorts of organic remains carried along with the 
waves. Probably also Aonides fulgens, Capitella capitata and Nereis 
diversicolor, which may occur together with Scolecolepis, adopt the 
same habit in such localities. Completely burrowed in the sand 
we also find here Aricia armiger O. F. Mtill., Nephthys ciliata 
