The Philippine Journal of Science. 



D. General Biology, Ethnology and Anthropology. 



Vol. VII, No. 2, April, 1912. 



A NEW PHILIPPINE FIDDLER-CRAB. 



By A. S. Peaksb. 

 (From the Zoological Laboratory, University of the Philippines.) 



The most abundant species of fiddler-crab along the esteros 

 near Manila has not been described. Believing the species to 

 be new, the writer prepared the following description while he 

 was serving as assistant professor of zoology in the University 

 of the Philippines. 

 Uca riathbunae sp. nov. 



Description. — Length of carapace about three-fifths its great- 

 est breadth, which is at the acute antero-lateral angles. 

 Carapace not very convex, smooth, anterior margin somewhat 

 arcuate; the regions all recognizable, but not clearly defined; 

 posterior border one-half the greatest breadth; lateral margins 

 not converging posteriorly. The crenulate line that bounds the 

 dorsal plane on each side is well marked two-thirds of the way 

 back and convergent posteriorly. The breadth of the front, 

 measured between the bases of the eye-stalks, is about one- 

 twentieth the greatest breadth of the carapace. The front is 

 spatulate, and its raised border is wider at the ventral margin 

 than the central groove. 



Orbits somewhat oblique; borders sinuous, both crenulate; 

 crenulations on the lower border progressively larger away from 

 median line; a line of fine crenulations below all the upper 

 border except the outer quarter; a row of tubercles on the floor 

 of the orbit inside the middle third of the lower border. 



Larger cheliped of male with hand nearly 3 times greater 

 than length of carapace; merus finely granulated on outer sur- 

 face, all margins denticulate, denticles larger at superior distal 

 angle ; carpus granulated on upper and outer surfaces, hairy 



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