Figure 190. — Pinnotlicrc.s- maculatus Say. Upper draw- 

 ing : male in dorsal view, 2 nun. indicated : Lower draw- 

 ing : female in dorsal view, 3 mm. indicated. 



as female, somewhat longer than wide, harder 

 than female. Kegions superficially defined more 

 by color than by structural prominence, light 

 areas mostly elevated, usually allowing pubescence 

 to wear; gastric, cardiac, and branchial regions 

 separated by broad, shallow, confluent indenta- 

 tions. Front broad, prominent, depressed, slightly 

 bilobed, approximately one-third width of cara- 

 pace. Orbits subcircular, eyes large. Antennae 

 somewhat longer than width of orbit. 



Chelipeds shorter than in female, hands 

 stouter. Walking legs wider, especially propodal 

 articles of first three legs ; posterior surface over- 

 laid with thin fringe of hairs attached near upper 

 margin ; last leg relatively shorter than in female, 

 not reaching propodus of third, dactyl more 

 nearly like third than in female. 



Abdomen at middle approximately one-third 

 width of sternum, gradually narrowing from 



third to seventh segment, sides of third convex, 

 of seventh obtusely rounded ; sutures between seg- 

 ments of abdomen and sternum with narrow lines 

 of dark pubescence. 



Measurements.— Carapace : length, 9.1 mm.; 

 width, 8.7 mm. 



Color. — Striking light dorsal color pattern of 

 bare spots on a background of dark pubescence 

 consisting of a median stripe constricted in mid- 

 dle and behind, a subtriangular spot on each side 

 in front of middle, and a linear spot on each 

 side behind. Chelipeds with dark pubescence on 

 inner and upper surface of carpus, a bit on upper- 

 surface of merus and inner side of palm proxim- 

 ally, otherwise scattered flecks on hands and walk- 



ing legs. 



Variations. — Young females resemble dark- 

 colored males except in shape of the abdomen and 

 the character of its appendages. Such females are 

 free swimming and range upward in length to 

 5.2 mm. More mature females, light colored and 

 commensal or parasitic in habit, range from 3.3 

 mm. in length upward. In such small and medium 

 sized females the long hair on the legs persists. 



Some males resemble mature females in colora- 

 tion and structure of legs, ranging in length from 

 about 4 mm. upward. Such males are commensal 

 or parasitic in habit. 



Individuals vary in stoutness of chelae, and in 

 length and curvature of dactyls on the second 

 legs. Normally this dactyl is like the dactyls on 

 the first and third legs, but may be straightened 

 and longer, and may occur on one or both sides of 

 an individual and in different individuals in the 

 same lot. 



Habitat. — Mature males and females are com- 

 mensal or parasitic in Mytilus edulis, Modiolus 

 modiolus, M. americanus, Mya arenaria, Aequi- 

 peeten gibbus, A. irradians, Placopecten magel- 

 lanicus, oyster (?), Atrina serrata, and in tubes 

 of Chaetopterus variopedatm, from Molgula ro- 

 busta, the pharynx of Bost richobranchus pilularis, 

 and on Asterias vulgaris. The free-swimming 

 stages have been found in bays and sounds. Sur- 

 face to 25 fathoms. 



Type locality. — Given as — "inhabits the muri- 

 cated Pinna of our coast." 



Known range. — Off Marthas Vineyard, Mass., 

 to Mar del Plata, Argentina. 



Remarks. — Though no detailed life-history 

 studies have been made on this species comparable 



MARINE DECAPOD CRUSTACEANS OF THE CAROLINAS 



207 



