53 
Et ganske lignende Dyresamfund har jeg fundet på flad Sand¬ 
strand lige udenfor Køge; kun var her tillige Unger af Cardinm 
ednle meget talrige. Også Oligochæter (Paranais littoralis (Miill.) 
Ørsted) fandtes i overordentlig stort Antal. Derimod var de blå¬ 
grønne Alger kun svagt repræsenterede, dannede ikke nogen Over¬ 
flade-Skorpe. Man kunde her ikke tale om nogen submers Sand- 
alge-Vade. — Kysten er her i det hele næppe flad nok til, at der 
kan blive Tale om nogen rigtig Sandvade — men den faunistiske 
Karakter minder dog så meget om den på de submerse Sandalge- 
Vader ved Læsø, at en Sammenstilling dermed må synes berettiget. 
Summary. 
The present paper deals with the Fauna of sandybeaches, 
mainly as observed on the Danish coasts. The details are mainly 
of local interest, but the ecological principles found to reign here 
are, evidently, of general value and will apply to animal life on 
sandy shores in general. 
The fauna of sandy beaches may be naturally divided into two 
main regions, the foreshore-zone and the tidal zone. The marine 
species inhabiting the foreshore are adapted to living on dry land, 
but can stand being occasionally washed over by the sea; those 
of the tidal zone remain true marine animals, but can stand lying 
dry during ebb-tide. The foreshore forms partly follow the water 
outwards with the ebb-tide and retreat for the rising flood, 
always keeping above the water; they are mostly fast moving ani¬ 
mals, which makes it possible for them as a rule to avoid being 
washed over by the waves. The freeswimning forms of the tidal 
zone keep below the water; if left by the retreating waves they 
quickly burrow themselves into the sand, remaining there till the 
water rises and sets them free again. The sedentary forms simply 
retreat into the sand during ebb-tide. 
In the fores hore two distinet communities are found. On 
flat beaches the surface of the sand is often woven together by a 
number of different Cyanophyceæ so as to form a greenish erust. 
