﻿NEW DECAPOD CRUSTACEANS FROM PANAMA 1 



By MARY J. RATHBUN 



The new species and subspecies here described form part of a large 

 collection made in Panama, in 1911, by Dr. S. E. Meek and Mr. S. F. 

 Hildebrand. A complete report on the material with illustrations of 

 the new forms will be published later. 



MACROBRACHIUM ACANTHURUS PANAMENSE, new subspecies 



Differs from typical M. acanthurus 2 in its constantly longer and 



more ascending rostrum, with more numerous spines T . There 



is an unarmed space behind the subterminal spines, which may, how- 

 ever, be interrupted by a single spine. The antennal peduncle just 

 reaches the end of the first segment of the antennular peduncle. The 

 merus of the legs of the second pair reach only to about the distal 

 third of the scales ; legs nearly smooth to the touch ; palms enlarged, 

 so that their circumference is greater than that of the distal end of 

 the carpus, and definitely shorter than the -fingers; fingers slender, 

 almost naked, taken together narrower than the palm. Telson con- 

 tinned posteriorly in an elongated triangular tooth, the base of which 

 is nearly as wide as the telson, and the sides nearly straight; this 

 tooth is twice as long as the inner of the side spines, except in the 

 young. 



Dimensions. — Male from Rio Calabre : length of body, 11.2 cm.; 

 length of foot of second pair, 71 mm. ; of merus, 13 mm. ; of carpus, 

 17 mm. ; of palm, 12 mm. ; of dactylus, 14 mm. 



Type locality. — Rio Calabre, Republic of Panama; March 18, 191 1. 



Type specimen— Male, Cat. No. 43656, U. S. Nat. Mus. 



Specimens from three different localities show varying combina- 

 tions of the characters which differentiate typical acanthurus from 

 acanthurus panamense. 



PSEUDOTHELPHUSA MASIMBARI, new species 



Carapace depressed ; gastric and branchial regions very slightly 

 and separately convex ; cervical suture curved ; surface covered with 

 a pavement of fine flattened granules which can be seen in large part 



1 This paper is the eleventh dealing with the results of the Smithsonian 

 Biological Survey of the Panama Canal Zone. 

 2 P alamort acanthurus Wiegmann, Arch. f. Nat., Jahrg. 2, Bd. 1, 1836, p. 150. 



Smithsonian Miscellaneous Collections, Vol. 59, No. 13 



