136 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



tion, larger and thicker on the distal part midway between upper 

 and lower margins, elsewhere smaller and to a large extent forming a 

 reticulate pattern ; proximally on the upper part of the outer surface 

 the raised reticulate lines are smooth, or non-granulate. 



The outer surface of the finger is rather regularly tapering, the 

 lower margin directed slightly upward, the superior margin nearly 

 straight; surface smooth; finger thick, the upper surface oblique or 

 beveled ; traces of fine teeth are visible on the prehensile edge. 



AXIUS?, species. 



Plate 57, fig. 10. 



Locality. — Panama Canal Zone. From near Mount Hope, in ditch 

 through swampy ground. About one-quarter mile from present sea 

 beach, 6 to 8 feet above high tide. Pleistocene series. D. F. Mac- 

 Donald, collector. April, 1911. Station 5850. Cat. No. 324250, 

 U.S-.N.M. 



Material. — A single movable spine, 6.7 mm. long, with the tip 

 broken off, resembles the styloid scaphocerite or movable acicle of the 

 outer antenna of some species of Axius. The spine is somewhat 

 3-angled, the most acute edge being dorsal, the two blunt edges being 

 nearer together and ventral. There are a few punctae : 4 large ones 

 in a row on the ventral surface; 2 large, external, far apart, just 

 below the upper margin; 4 small ones, internal, 3 of which form a 

 triangle near the middle, while the other is nearer the distal end. 



Family CALLIANASSIDAE. 



KEY TO THE SPECIES OF CALLIANASSA HERE DESCRIBED. 



The material is insufficient to distinguish between the larger and 

 the smaller chela of the same pair, which also may vary in shape and 

 size in the two sexes. 

 A 1 . Manus and carpus meeting in an oblique line. 



B 1 . Lower margin of manus serrated ovalis, p. 137 



B 2 . Lower margin of manus smooth lacunosa, p. 13S 



A 2 . Manus and carpus meeting in a vertical line. 



B\ Lower margin of manus directed forward and upward, at least in part. 

 C\ Palmar portion of manus distinctly longer than high. 

 D 1 . Palm compressed. 



E\ Palm elongate; margins strongly convergent elongata, p. 139 



E 2 . Palm less elongate ; margins moderately convergent scotti, p. 140 



D 2 . Palm swollen jmoinensis, p. 142 



C 2 . Palmar portion of manus about as long as high, or shorter. Upper 



margin of manus directed forward and downward toward the lower 



margin. 



D 1 . Immovable finger very thin, a cross-section near its base being more 



than twice as long as wide. A strong tooth in the sinus between the 



fingers or on the base of the immovable finger spinulosa, p. 143 



D 2 . Immovable finger thicker, a cross section near its base being less 

 than twice as long as wide. A tooth in the sinus between the fingers 

 but near the base of the dactylus tenuis, p. 144 



