156 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



convex from top to bottom. The prehensile edge has traces of 2 

 small teeth, one near the base and one at about the distal third. 

 There are also various depressed granules or pits, namely, a row of 

 5 small ones on the upper margin; opposite the distal one of these 

 there is a larger one on the inner surface; and 3 or 4 on the outer 

 surface. These are all sunken so that they do not project above the 

 present surface, which is not the true outer surface. 



This finger is not quite so flat inside as H. chiliensis. 



Measurements. Length of dactylus, 13.6 mm.; height at middle. 

 3.6 mm. ; thickness at middle, 2.7 mm. 



CALAPPA COSTARICANA, new species. 



Plate 57, fig. 24. 



Type-locality. Costa Rica: City of Port Limon. Port Limon 

 formation. Pliocene series. Dr. L. A. Wailes. 4269. 



Flolotype.C^t. No. 324240, U.S.N.M. A triangular fragment 

 measuring about 9 mm. on each margin, representing the propodal 

 finger and the infero-distal portion of the palm of a left chela of 

 the weaker form that is, without a strong submarginal tooth or lobe 

 characteristic of the stronger chela in Calappa. Lower margin very 

 sinuous, the tip of the finger directed upward, proximal half of 

 margin armed with 6 strong tubercles directed distally. Just above, 

 on the outer side, and beginning nearer the finger-tip there is a row 

 of 11 smaller tubercles, normal to the surface. The prehensile edge 

 is nearly straight, inclined at an angle of about 75 with the lower 

 margin of the palm, and is furnished with 6 large, unequal tubercles, 

 which end at the small sinus which ordinarily exists just beloAv the 

 raised margin surrounding the articulation with the dactylus; on 

 the upper side of this sinus are 2 small tubercles, and above this 

 point, the specimen comes to an end. The outer surface is covered 

 with upward of 40 flattened scale-like tubercles pointing upward; 

 they are separated from the submarginal row by a smooth depres- 

 sion. The propodus is thick and the inner surface is beveled, the 

 bevel for the most part smooth ; remainder of inner surface studded 

 with very unequal pearly granules and tubercles ; interspace crowded 

 with fine punctae ; 2 sinuous ridges run toward the finger-tip. 



This species resembles C. gallus (Herbst) 1 , which is found living 

 at the present time from Florida Keys to Bahia, Brazil. The fossil 

 species differs in the very prominent tubercles of the lower margin 

 of the palm and the longer tubercles of the submarginal row just 

 above, on the outer surface. 



1 Cancer gallus Herbst, Natur. Krabben u. Krebse, vol. 3, pt. 3, 1803, pp. 18 and 46, 

 pi. 58, flg. 1. 



