﻿NO. 7 EMERITA ANALOGA WEYMOUTH AND RICHARDSON 9 



slit-like mouth. Portions of the first maxilliped and of the first and 

 second maxillae flank the elongate mouth and are provided with long 

 stiff setae, which are curved over the margin and directed upward into 

 the gullet. These three comb-like structures apparently serve as 

 valves to prevent the escape of the minute food and to work it into the 

 mouth. The mandibles, which correspond closely with Smith's de- 

 scription 12 of those in E. talpoida, are very much reduced, and are so 

 soft as to be of no use in mastication, thus illustrating in a striking 

 fashion the degree of adaptation to the peculiar form of food which 

 has taken place in this animal. 



The contents of a considerable number of stomachs were examined 

 at different times and were always found to consist of the same kind 

 of material; chiefly shells of various diatoms, masses of brownish 

 oily matter apparently derived from the diatoms, radiolarians, foram- 

 inifera, spicules of unrecognized origin, what were probably one- 

 celled algae, and considerable amounts of sand — about what would be 

 obtained by unselective straining of the water along shore. No food 

 has been seen which appeared to come from the breaking up of larger 

 animals, and indeed it is difficult to see how Emerita could do this, 

 in view of the complete absence of chelae or other grasping organs, 

 and of hard grinding surfaces on any of the mouth parts. 



A striking contrast is presented by Blepharipoda, where well- 

 developed chelae are present together with a spiny merus on the third 

 maxillipeds and heavy and well-calcified mandibles of the common 

 type. The antennae are also much smaller than those of Emerita. 

 Unfortunately no fresh specimens were available for the examination 

 of the stomach contents. 



RESPIRATION 



A number of devices are found in burrowing crabs for the removal 

 from the respiratory stream of particles of sand or mud, which might 

 be harmful to the gills. In some the water is inhaled between the 

 chelipeds and the ciliated pterygostomian region, thus straining out 

 the sediment (Calappa™ Bathynectes u ). Others, however, have the 

 antennules (Albunea 15 ) or the antennae (Corystes 16 ) modified to 

 form a tube through which water may be drawn from above the 



Trans. Conn. Acad., Vol. 3, p. 338. 1877. 

 Garstang, Quart. Journ. Micr. Sci., Vol. 40, p. 212. 1897. 

 1 Garstang, Journ. Mar. Biol. Asso., Vol. 4, p. 396. 1897. 

 1 Garstang, Quart. Journ. Micr. Sci., Vol. 40, p. 224. 1897. 

 Garstang, Journ. Mar. Biol. Asso., Vol. 4, p. 224. 1896. 



