X, D, 1 Coivles: Tropical Crustacea, II 13 



habitat. Then begins the interesting process of feeding which 

 was first described by Fritz Miiller ^ for Atyoida potimirim - 

 (now known as Atya potimirim) . 



The method as observed by me is as follows : Usually, as soon 

 as the atya becomes settled, the first and second pairs of legs 

 are extended anteriorly, the chelse — 4 in all — open, and the 

 brushes of hairs spread out so as to make wide open, almost 

 funnel-shaped strainers, whose larger open ends are directed 

 toward the stream. Each chela has 2 strainers, making 8 

 strainers in all. When a pair of strainers has collected enough 

 food, the chela is closed, the hairs become grouped into a single 

 brush, the chela turns backward on its basal end as an -axis 

 through almost 180°, and finally the brush of hairs is applied 

 to the mouth where the food is extracted. The maneuver last 

 described is executed very quickly, in less than half a second, 

 and when it is completed the chela returns to its former position 

 and opens and the strainer begins to perform its function again. 

 The other strainers when filled are handled in the same way. 



There seems to be no regularity in the order in which the 

 chelse are brought to the mouth, it depends apparently upon 

 the rapidity with which the strainers collect the food. A micro- 

 scopic examination of the hairs of the strainers shows that each 

 has finer hairs growing from it and they probably interlace, 

 thus increasing the collecting power of the strainers. In con- 

 clusion, then, Atya molluccensis is, primarily at least, a feeder 

 on small organisms or other finer particles of food which are 

 floating in the water, and judging from observations of the 

 feeding and other habits of the animal in its natural habitat, 

 it is probable that the method described above is the only one 

 used. 



The species of Caridina which 1 have collected have not been 

 identified, but I find that they all have similar habits. They 

 occur in springs, shallow streams, and lakes in the Philippines 

 and like the species of Atya are good crawlers. 



The first and second legs are somewhat similar to the same 

 structures in the genus Atya, except that the chelse have a dif- 

 ferent form and the hairs are shorter and less numerous. In 

 all my observations of these crustaceans, both in the field and 

 in captivity, I have never seen the hairs spread out to form a 

 strainer, nor have I seen these animals taking advantage of the 



^Kosmos. Stuttgart (1881), 9, 117. 



' I am much indebted to Dr. W. T. Caiman, of the British Museum, for a 

 copy of Miiller's paper. 



