﻿8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 59 



dad, California, were examined and a few diatoms were found en- 

 tangled in the hairs together with sand grains and unrecognizable 

 debris, similar to that obtained from the stomach. 



The mouth parts are admirably adapted for the manipulation of 

 these minute organisms which the antennae have strained from the 

 waves. In the normal position of the parts one is struck by the great 

 development of the external (third) maxillipeds (fig. 4, pi. 1), which 

 like double doors cover the entire buccal region of this remarkable 

 animal. Along the median line they meet closely at the base ; near the 

 distal end they diverge slightly, but the longer hairs in this region still 

 serve to close the cavern. Posteriorly the closely approximated bases 

 of the first pair of pereiopods curve forward and overlap slightly 

 the posterior edge of the external maxillipeds, completely closing the 

 cavern in that direction. A small diamond-shaped hole which would 

 otherwise be left in the median line between their bases and the 

 proximal ends of the third maxillipeds is closed by the tips of the 

 palps. Laterally, the external border of the operculiform ischial 

 joint, which is also ciliated, comes accurately in contact with the 

 pterygostomian plate for rather more than half its length. Anterior to 

 this, it fits against the basal portion of the antennae, so as to com- 

 pletely close the cavity at this point. The cavern is least complete in 

 front. Immediately below the antennules and eyes lie the crossed 

 distal portions of the antennal peduncles, and against these the tips 

 of the third maxillipeds rest. Crannies which might otherwise remain 

 open are stopped by the greater development of hairs in this region 

 (fig. 7, pi. 1). When the antennae have been folded, they are thus 

 inclosed in a cavity in which the food they have caught may be re- 

 moved and transferred to the mouth without loss. For this use the 

 other mouth parts are well adapted. The relation of the parts is well 

 shown by fig. 7, pi. 1, which represents the buccal region exposed by 

 turning back the external maxillipeds. 



Careful observation shows that when Emerita is undisturbed it folds 

 in the antennae separately as the wave runs off the beach. Each 

 flagellum is allowed to trail out nearly parallel with the body, and then 

 is folded up and withdrawn under cover of the third maxillipeds with 

 such a rapid motion as to escape analysis. Inside the buccal cavern 

 each antenna is coiled loosely with the food-laden bristles pointing 

 toward the center (fig. 7, pi. 1). From the anterior portion of the 

 cavern the two palps of the second maxillipeds, armed with bristles 

 arranged like those of a tube brush, project down into the coil of the 

 antennae. These are apparently used to scrape the food toward the 



