DECAPOD CRUSTACEANS OP THE BEAUFORT, N. C, REGION. 403 



Family PORCELLANIDAE. The porcelain crabs. 



Galatheidea, usually of a crablike form, having the abdomen closely folded beneath 

 the thorax, the stalk of the second antenna composed of four articles, the arthrobranchs 

 normally placed, and the third maxillipeds without mastigobranchs. 



Of the 8 genera now recognized in this family, 5 have representatives in the Beau- 

 fort fauna. 



KEY TO THE GENERA OF THE BEAUFORT REGION. 



a. Carapace depressed, chelipeds large. 



6. Carapace subcircular, about as broad as long, chelipeds broad and flat, 

 c. Epimeral pieces of carapace separated by membranous interspaces; body smooth, hands very 



rough Pachycheles. 



cc. Epimeral pieces of carapace not separated by membranous interspaces. 

 d. Basal article of antenna little developed, the fiagellum not excluded from the orbit. 



Peirolisihes. 

 dd. Inner angle of basal article of antenna expanded to meet the superior margin of the carapace 



and excluding the flagellura from the orbit Porccllana. 



bb. Carapace oval, broader than long, hands slender and distorted Polyonyx. 



aa. Carapace subcylindrical, much longer than broad, chelipeds small Euceramus. 



Genus PORCELLANA Lamarck. 



PoTcellana Lamarck, 1801, p. 155: restricted by Stimpson, 1858. p. 242. 



KEY TO THE SPECIES OF THE BEAUFORT REGION. 



a. Body and appendages comparatively smooth sayana. 



aa. Body and legs with numerous tuberculate elevations sonata. 



Porcellana sayana (Leach). PI. xxix, fig. 7. 



Pisidia sayana Leach, 1820, p. 54. 



Porcellana ocellaia Gibbes, 1850, p. 190; Kingsley, 1878, p. 325. 



Porcellana sayana Kingsley, 1880, p. 407; Benedict, 1901, p. 137. 



Integument minutely granulate, body depressed, carapace a little longer than wide, dorsal surface 

 slightly convex, meeting the lateral parts in a sharp ridge which ends in a slight shoulder a little behind 

 base of antenna. Rostrum triangular, its tip abruptly decurved; orbit with a strong tooth at inner angle 

 separated from the rostrum by a wide and rather deep notch, outer angle much less conspicuous. Cer- 

 vical groove lightly impressed. 



Antermae slender, longer than carapace. Chelipeds strong and heavy; hand as long as or longer 

 than carapace, its outer margin fringed with long hairs; fingers short, ciu-ved and bent. Proximal inner 

 angle of carpus and distal inner angle of meros produced, forming lobes. Second, third, and fourth 

 legs normal; fifth legs reduced and carried above the others. Abdomen weak, much flattened; uropods 

 small and weak; telson divided into about seven small plates by oblique and longitudinal impressions. 



Length of a male: Carapace, 9 mm.; hand, 9.5 mm.; width of carapace, 8.5 mm. 



Color in life, reddish or rusty brown with irregular longitudinal white lines, of which the median 

 one is broadest and expanded anteriorly; hands and carpi with white spots on a red ground; smaller 

 legs with transverse reddish bars. In alcohol the red color disappears and the animal becomes perfectly 

 white. 



Porcellana sayana is not infrequently taken in the dredge in various parts of the harbor and along 

 the neighboring coast. It is most often found in some crevice in a cluster of oyster shells, but is some- 

 times found as a commensal of the hermit crab (Pagurus pollicaris) in the shell of some gastropod. It 

 has also been collected among the rocks of the jetties near Fort Macon. 



An account of the zoea of this crab, secured from eggs hatched at Beaufort, has been given by Brooks 

 and Wilson. 3 



a Johns Hopkins University, Biological studies, vol. n, no. i. p. 58-64, pi. vi, vn, 1881. 



