42 Description of Two New Species of Terrestrial 



from St. Lawrence Co.,"- and is stated to occur in both St. Law- 

 rence and Jefferson counties. Its describer has evidently failed 

 to consult the "Histoire jSTaturelle des Poissons," or he would 

 have discovered that the same name had already been 

 given to a species of South America, which has hitherto been 

 considered as a congener of the North American Pimelodus 

 catus. The Pimelodus gracilis of Plough is said to have 

 from twenty-two to twenty-four anal rays, twenty -two branched 

 caudal rays, and maxillary barbies " extending back to the tips 

 of the gills," in which respects it differs from the present 

 species. 



IX. — Description of Two New Species of Terrestrial Grapsoid 

 Crustaceans from the West Indies. 



By TiiEo. Gill. 

 Read December 20, 1858. 



CAEDISOMA, LAT. 

 1. €arcli§oiiia cliiirniiiii, Gill. 



The carapace is longitudinally arched and transversely 

 nearly horizontal ; on each side it is distinctly defined anteriorly 

 by an elevated line which is boldly curved outwards. The 

 sides are little convex anteriorly, but convexly tumid poste- 

 riori}'. The surface of the carapace has the same order and 

 arrangement of its areolar areas as that of Cardisoma guanhumi 

 (Lat.). The postorbital tooth is elongated, triangular, and trilate- 

 ral, acute and small : behind this and separated by a groove is 

 a smaller one. 



The external maxilliped has its meros or fourth joint almost 

 obliquely truncated, cordiform, and with its internal side with a 

 moderately gibbous margin. 



* In " Fifth Annual Report of the Regents of the University on the Condition 

 of the State Cabinet of Natural History," die, Albany, 1852. 



