126 PROCEEDINGS OF THE NATION AL MUSEUM. vol.47. 



FamUy OCYPODID^. 



Su.ljfam.ily OCYTODIN^aE. 



UCA MONILIFERA,! new species. 

 Plate 9. 

 Eurychelits monilifer L. Agassiz, MS. label. 



Type-locality. — Guaymas, Mexico; Capt. C. P. Stone, U. S. N., 

 collector, 1859. 



Type.— Male, Cat. No. 1578, M. C. Z.; 1 male paratype iii U. S. 

 National Museum, Cat. No. 22180. 



Dimensions.— Length of carapace of type male 28.7 mm., width at 

 antero-lateral angles 45.4 mm. 



This is the Pacific representative of the well-known fiddler crab 

 with narrow front and broad fingers, TJca maracoani (Latreille)^, 

 which is distributed on the Atlantic coast of South America from 

 Cayenne to Kio de Janeiro. 



Z7. monilifera is considerably larger than maracoani, a« the carapace 

 of a large specimen of the latter measures 22X34 mm. There is no 

 raised or granulated line bounding the dorsal plane on either side, 

 but the dorsal rounds smoothly into the lateral surface. As in 

 maracoani the anterior margin of the carapace or superior margin of 

 the orbit is transversely sinuous, forming a triangular tooth at the 

 antero-lateral angles, and the front between the eyes is extremely 

 narrow and spatuliform, its median furrow linear and not reachmg 

 the broadest part of the spatula. 



The lower margin of the orbit is deeply crenated or turreted 

 throughout. 



The large cheliped of the male is much smoother than in the Atlan- 

 tic form. The inner border of the arm has a large lammar expa^ision 

 directed upward, edge arcuate, denticulate. The wrist is more 

 elongate than in maracoani. The tubercles of the palm are few and 

 indistmct. Fingers quite smooth except at the margins and at the 

 base of the dactylus, where there are a few depressed tubercles. On 

 the immovable finger there is, as in maracoani, a raised line just above 

 the lower margin and continued backward on the palm; there is, 

 however, no broad lobe or tooth on the proxmial half of the prehensile 

 edge. The movable finger has a different shape from that of the 

 allied species; while the upper margin is a regular and moderate 

 curve, the prehensile edge is concave for its basal three-eighths, then 

 straight to near the tip, forming a small tooth at the meeting of the 

 two Imes; this brings the widest part of the finger just proximal to its 

 middle. In maracoani, the widest part of the finger is near its distal 



> I have adopted the specific name used by Prof. Louis Agassiz on a Museum label, but hitherto 

 unpublished. 

 ' Ocypode maracoani Latreille, Hist. Nat. Crust., vol. 6, 1803 (an XI), p. 46. 

 Oelasimus Maracoani Milne Edwards, Ann. Sci. Nat., ser. 3, vol. 18. 1852, p. 144 [lOS], pi. 3, figs. 1-16. 



