12 Bulletin Wisconsin Natural History Society [Vol. 11, Nos. 1-2 
the domination of the ocean, for lichens, crickets, and other organ- 
isms that frequent rocky places in the fields further from the 
shore are wholly lacking. 
2. The Baianus Zone 
In this stratum, where the exposure and variation are greater 
than anywhere else on the beach, algae are absent, and “ acorn” 
barnacles ( Baianus ) greatly exceed all other animals in abundance 
Fig. 3. Baianus on Vertical Rock Wall. 
(fig. 3). Mytilus occurs in protected crevices, however, clear to 
the top of the barnacle zone; Littorina litorea is found in similar 
situations (fig. 4, 5) and L. rudis often occurs on the bare rocks 
above the barnacles. Anurida breeds in empty barnacle shells. 
In the pools of this zone dipterous larvae, Mytilus , Carcinides, 
Gammarus locusta, Idothea baltica, Baianus, P ary dr a, Littorina 
litorea, and L. rudis were often common; also Campanula and 
Sagartia in protected situations. 
