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containing the lens, faces one of the flattened surfaces of the body. 

 When this surface is up the eye is to the left and when it is down 

 it is to the right of the median line (fig. 1). 



The tadpoles of Amaroucium constellatum and A. pellucidum 

 are essentially the same in form and in structure in so far as it 

 concerns behavior. They differ, however, greatly in size, 

 constellatum being approximately 2.25 mm. and pellucidum 

 1.5 mm.* long. 



Fig. 2 Eye of tadpole of Amaroucium constellatum after a camera outline 

 by Grave from a living specimen, e, ej'e-cup; I, lens; a-a, longitudinal axis^of 

 body; P., posterior surface. 



Colonies kept in running sea-water in the laboratory produce 

 larvae for a number of days. These are liberated throughout 

 the entire day, but not in abundance except in the morning about 

 sunrise when they can be collected in fairly large numbers at 

 the surface of the water on the side of the jar facing the light. 

 There is thus a certain periodicity in the liberation of the tadpoles. 

 The factors involved in this periodicity have, however, not as 

 yet been definitely ascertained. 



