DECAPOD CRUSTACEANS OF THE WEST INDIES 89 



8. Rostrum with two or more teeth on dorsal margin 9 



Rostrum with single dorsal tooth or unarmed 10 



9. Rostrum reaching at least as far as end of antennal scale, armed with six 



to eight dorsal teeth Troglocubanus eigenmanni (p. 113) 



Rostrum not reaching beyond end of antennular peduncle, armed with two 

 or three dorsal teeth Troglocubanus gibarensis (p. 113) 



10. No antennal spine on carapace Troglocubanus inermis (p. 114) 



Antennal spine present, even if inconspicuous 11 



11. Rostrum with ventral margin straight or concave throughout; third and 



fourth pereiopods with propodus more than three times as long as dactyl. 



Troglocubanus calcis (p. 112) 



Rostrum with ventral margin convex in proximal two-thirds; third and 



fourth pereiopods with propodus not more than two and one-half times as 



long as dactyl Troglocubanus jamaicensis (p. 115) 



Genus Macrobrachium 



17. Macrobrachium acanthurus (Wiegmann) 



Figures 20, 25a, g 



Palaemon acanthurus Wiegmann, 1836, p. 150 [type-locality: "Brazilian coast"]. 



Palaemon forceps H. Milne Edwards, 1837, p. 397 [type-locality: Rio de Janeiro]. 



Palaemon Swainsonii (Leach ms) White, 1847, p. 78. 



Palaemon mexicanus De Saussure, 1857c, p. 504 [type-localities: Cuba and 

 Mexico]. 



Macrobrachium longidigitum Bate, 1868, p. 365, pi. 31: fig. 2 [type-locality un- 

 known]. 



Palaemon dasydactylus Streets, 1871, p. 225, pi. 2: figs. 3, 3a [type-locality: tide- 

 water of the Rio Coatzacoalcos, Estado de Veracruz, Mexico]. 



Palaemon sexdentatus Streets, 1871, p. 226, pi. 2: figs. 4, 4a [type-locality: tide- 

 water of the Rio Coatzacoalcos, Estado de Veracruz, Mexico]. 



Palaemon PotieU MuUer, 1892, p. 181 [type-locality: Itajai, Estado de Santa 

 Catarina, Brazil]. 



Bithynis acanthurus. — Rathbun, 1900b, p. 154. 



Bilhynis forceps. — Young, 1900, p. 487. 



Macrobrachium acanthurus. — Pearse, 1911, p. 111. — Holthuis, 1952, p. 45, pi. 8; 

 pi. 9: figs, a, b. 



Diagnosis. — Carapace witli antennal and hepatic spines, watliout 

 brancliiostegal spine. Rostrum usually reacliing bej^ond end of 

 antennal scale, nearly straight in large specimens (fig. 206), upcurved 

 in young adults (fig. 20a.) ; armed with 9 to 1 1 dorsal and 4 to 7 ventral 

 teeth; posterior two teeth of dorsal series on carapace behind level of 

 orbital margin, first usually separated from second by interval longer 

 than that between second and third. Eyes large, cornea well pig- 

 mented. Second pereiopods of adult male subequal, slender (for the 

 genus); fingers nearly as long as palm, meetmg throughout their 

 length, covered with dense, short fur, opposable margin of each 

 armed near base witli distinct tooth; palm subcylindrical, four and 

 one-half to five and one-half times as long as wide, with several 



