150 MINNESOTA BOTANICAL STUDIES. 



6. Amphiroa cretacea. 



Occurs below the Phyllospadix on the northwest and south- 

 west, three feet below the surface. 



7. Laminaria cloustoni. 



One plant was found in a crevice on the south and one on the 

 east three feet below the surface. 



8. Codium mucronatum. 



A few plants occur on the north one and one half feet below 

 the surface. 



9. Costaria turneri. 



One plant was found one foot below the surface on the west 

 and one three feet below the surface on the east. 



10. Laminaria bullata. 



One plant was found on the east end three feet below the 

 surface. 



11. Codium adhaerens. 



A small amount occurs on the southwest end, one foot below 

 the surface. 



Pool No. V. 



Location. — Mid-tide pool. On a level three feet below No. 

 4. Distant from the edge of the ridge one foot. 



Exposure to the Tide. — The waves enter from the east and 

 southwest. The waves thus coming from nearly opposite 

 directions frequently meet and give rise to a strong vortex- 

 motion. 



Shape and Dimensions. — Circular. Edge overhanging on 

 the north and east. The sides slope gradually for about two 

 and one half feet and then recede. On the south and west the 

 sides recede from the very top. Sides, in general smooth bui 

 pitted somewhat with small holes. 



Bottom covered with small pebbles which are kept in almost 

 constant movement by the vortex action mentioned above. 



Diameter four and one half feet. Depth four and one half 

 feet. 



Flora: Kind and Distribution. 



1. Corallina aculeata. 



Occurs on the northeast side for about two and one half 

 feet. 



