170 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



longitudinal punctate impressions on the outer surface, the larger 

 dactylus is more arched than the smaller; the fingers cross each 

 other a little before the tips, at least in the smaller chela; the end 

 of the larger immovable finger is broken off ; prehensile edges armed 

 with large irregular, separated teeth, the basal tooth of the larger 

 dactylus being of enormous size and directed obliquely backward 

 as in Scylla. The distal half or two-fifths of the fingers is dark- 

 colored, also the prehensile teeth. 



The 3 pairs of ambulatory legs are only partially preserved ; they 

 would, if extended, reach about to the middle of the manus of the 

 chelipeds; the first five segments are stout; the propodus, of which 

 only impressions exist, has a groove through the middle and appears 

 to be flattened ; the dactylus can not be made out with any degree of 

 certainty; the swimming- feet, or those of the last pair, are very 

 broad, the carpus is as broad as long; the propodus is about twice 

 as long as broad; the dactylus is lanceolate-oval, about 2 times as 

 long as broad. * 



Another specimen (paratype a) lacking the dentate border of the 

 carapace, and all appendages except the coxal joints of the legs, was 

 taken from the Gatun formation, Gatun Locks, by D. F. MacDonald, 

 May, 1911. Station 5900. Cat. No. 324241, TJ.S.N.M. 



A much smaller specimen (paratype 6) which is identified as 

 probably belonging to this species is labeled : " Near Gatun. Mio- 

 cene. Eev. G. Rowell. Cat. No. 113706, U.S.N.M." It is probably 

 from the Gatun formation. A portion of the left side of the cara- 

 pace is preserved, showing the base of the 3 posterior of the antero- 

 lateral teeth ; on the under side is shown the margin of the buccal 

 cavity, fragments of a maxilliped and the base of the cheliped. A 

 separate specimen (paratype c), from the same locality, is the left 

 manus, somewhat crushed, proximally incomplete and lacking the 

 propodal finger, but with the base of the dactylus attached, including 

 the first or large, rounded tooth. 



A fragment of a finger bearing 3 teeth (paratype d) is referred 

 here; the smooth outer layer is almost gone except a few bits near 

 the teeth; it was taken from the 85-foot cut on north side of big 

 swamp on relocated line of the Panama Railroad, 1 to 2 miles be- 

 yond Camp Cotton toward Monte Lirio ; Gatun formation ; Miocene 

 series: D. F. MacDonald and T. W. Vaughan, collectors, 1911; 

 Station 6030; Cat. No. 324242, U.S.N.M. 



I refer here with doubt a curved fragment of a thick-shelled species, 

 which has a large tooth occupying half its surface. It may belong 

 near one of the articulations. It was taken at Station 60336, in the 

 upper part of the lowest bed, Gatun section; Gatun formation; 

 Miocene series; MacDonald and Vaughan; 1911; Cat. No. 324286, 

 U.S.N.M. 



