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PROCEEDINGS OF THE 



[May, 1854. 



Description, with figures, of six species of Porcellana, inhabiting Eastern Coast 

 of North America. By L. R. Gibbes. 

 A.— FRONT NEARLY STRAIGHT. 

 1. Porcellana macrocheles. Plate I. fig. 5, natural size. 

 Synonyme. P. macrocheles, Gibbes, Pro. Am. As. Sci., 3d vol. p. 191. 1850. 



Description. — Body thick, carapax transverse, length to breadth as three 

 to four, convex longitudinally; front very slightly prominent, anterior edge 

 nearly straight, eyes small, not prominent ; external antenna with massive 

 basal segment, completely filling up the groove in which it is placed in the 

 shell, and bearing on its outer angle the moveable peduncle, which is thus 

 entirely separated from the eye ; the groove is not prolonged backwards under 

 the lateral portion of the shell as usual, but that course is marked by a fis- 

 sure ; the filament about as long as the carapax. 



Anterior feet unequal, right largest in the three individuals examined ; third 

 segment conspicuous, subcubical, rounded posteriorly, with a projecting la- 

 mellar lobe anteriorly ; carpus as long as the carapax, thick, subcylindrical, 

 with anterior edge curved, lamellar, projecting, without teeth or spines ; the 

 larger hand, long, thick, subcylindrical, anterior edge for three-fifths of its 

 extent straight, ciliate, with thumb falcate, acute, and finger straight, hooked 

 at tip, with a large tooth on middle of trenchant edge ; larger hand with fin- 

 ger is twice the length of the shell; smaller hand, more slender and com- 

 pressed. The four poster ior feet, with short tarsus armed with short spines 

 crowded at the tip. 



Color, whitish or flesh color. 



Geo. Distr. — Coast of South- Carolina, first found by Dr. T. L. Burden, 

 of Charleston, a single individual only; a few more have been since obtained 

 by others. Readily distinguished by its straight front, and transverse subcy- 

 lindric body. 



Remarks. — I find that the specific name had been previously used by 

 Pceppig, but as the species so named by him, is the same as Guerin's P. vio- 

 lacea, and this last name has priority, the specific name above used may 

 stand. 



B.— FRONT PROMINENT, TRIANGULAR, NOT DENTATE. 



2. Porcellana magnifica. Plate I., fig. 3, natural size. 

 Synonyme. P. magnifica, Gibbes, Pro. Amer. Assoc., 3d vol. p. 191. 1850. 



Description. — Carapax with length and breadth nearly equal, smooth, 

 polished, punctate, with traces of rugae near the lateral edges, which are 

 marked with a moderately distinct line, no spines in any part ; front not trifid, 

 moderately prominent, triangular, with a central linear depression ; external 

 antennae, with moderately robust basal segment, furnished with a stout spine 

 on the inside or side next the eye, spine stout, curved, pointing towards the 

 eye. 



