﻿NO. 7 EMERITA ANALOGA WEYMOUTH AND RICHARDSON II 



is in, by means of the antennular tube, and then forced out- into the 

 surrounding sand. When swimming about or resting on the surface 

 of the sand, the water is taken in at the sides of the carapace and 

 forced out through the antennular tube, the direction of the current 

 thus being that common to most crabs. At other times, possibly 

 when the sand is uncovered, this may also prove to be the more 

 serviceable method. Reversal of current took place in the animals 

 observed in the aquarium at times apparently because of irritation 

 due to the carmine or to stimulation with a pencil point and again 

 without visible cause. 



Reversal of current has been described by Garstang in Corystes 17 

 and Portumnus 1S and the same thing has recently been observed by 

 us in the case of Cancer ma gist er, the common edible crab of the 

 Pacific Coast. It is apparently a much more common phenomenon 

 than is ordinarily supposed. 



SUMMARY 



The present paper treats of the habits of Emerita analoga [=Hippa 

 analoga] of the western United States, particularly in regard to bur- 

 rowing, feeding and respiration. 



i. The food of Emerita analoga consists of microscopic organisms 

 strained from the waves, to which it is constantly exposed, by means 

 of the greatly developed antennae. This is shown by examination of 

 stomach contents and observation of living animals under natural 

 conditions. 



2. The structure of the peculiar antennae, the uses of which have 

 hitherto been incorrectly inferred, of the greatly reduced mandibles, 

 and the remainder of the greatly modified mouth parts are remarkably 

 adapted to this form of feeding, and unfitted for any other. 



3. The burrowing habits necessitated by their peculiar habitat in 

 the shifting sand within the wash of the waves is accompanied by a 

 large number of adaptive structures, among which are the oval form 

 of the body, the expanded dactyls of the ambulatory legs, and the form 

 and position of the uropods. 



4. Respiration, in accordance with their burrowing habits, is carried 

 out by a specialized apparatus similar to that described by Garstang 

 for Albunea. Water may be drawn from above the surface of the sand 



Journ. Mar. Biol. Asso., Vol. 4, p. 228. 1896. 

 ! Op. cit., p. 405. 



