larval development listing three zoeal stages and 

 one megalops stage, and compared these to simi- 

 lar stages they had previously described for S. 

 cinereum. The authors also concluded that photo- 

 period has no observable effect on development. 



Crichton (1960) studied a colony of S. reticula- 

 tum in Delaware. With the aid of rubber casts, he 

 found that the species digs burrows which may 

 have several openings leading at a gentle slope to 

 a depth of 3 or 4 inches where a series of more or 

 less level corridors curve, twist, and often inter- 

 connect. Each corridor usually leads to a vertical 

 shaft as much as 30 inches deep and usually filled 

 with water. Burrows are communal, containing 

 a male or two and several females. Crichton 

 found that this species will eat fiddler crabs (the 

 burrows occasionally intersect) when it can cap- 

 ture them; however, the usual diet is Spartina, 

 and swaths often are cut through this marsh grass. 

 Burrowing action of the crab tills the land, in- 

 creases erosion, and turns over the cord grass more 

 rapidly than the annual decay cycle could do it 

 unaided. 



Teal (1959) found this species active on Geor- 

 gia marshes when the tide was high or the sky 

 cloudy. "When the marsh was exposed, the crabs 

 were found in burrows, usually near the top, in 

 air or water. Respiration rates were higher in 

 water than in air. Gray (1957) found the gill 

 area of S. reticulatum to be relatively low as com- 

 pared with other species living in a similar habitat 

 (Uca pugnax and minax). He found S. reticula- 

 twm to be more robust but less active than the close 

 relative, S. cinereum. 



Humes (1941) described a harpacticoid cope- 

 pod (Canerincola plwmipes) from the gill cham- 

 bers of this crab. 



Sesarma (Holometopus) cinereum (Bosc). Wharf crab: 

 wood crab; friendly crab; square-backed fiddler 



Ficure 206 



Orapnu.1 einerru* Rose [isol or 1802], p. 204, pi. 5, fie. 1, 

 Sesarma cinereum: Rathbun, lfUSh. p. .too, text-flg. 149, pi. 83 

 (rev.). 

 Sesarma einerca: Hny and Shore, 1 !»1 8. p. 440, pi. 36, fig. 11. 



Recognition rim meters. — Carapace rectangular, 

 nearly uniform in width throughout ; regions well 

 M'']: surface nearly smooth, punctate, rough 

 with squamiform tubercles toward front; supra- 

 frontal lobes well marked, inner pair widest. 

 Front 4 times us wide as high, widening helow, 



Figure 206. — Sesarma (Holometopus) cinereum (Bosc). 

 Animal in dorsal view, 5 mm. indicated. 



somewhat four-lobed in dorsal view, lower edge 

 sinuous. Outer orbital angle acute. Lower sur- 

 face of carapace covered with fine net of genicu- 

 late hairs. 



Chelipeds heavy; merus and carpus covered 

 with short transverse lines of scabrous granules; 

 merus with upper edge sharp, inner edge irregu- 

 larly dentate with a triangular laminar expansion 

 on distal half; carpus with inner angle rounded. 

 Palm nearly twice as high as upper length; outer 

 surface covered with scabrous granules arranged 

 in parallel lines near upper margin; inner face 

 coarsely granulate, with short prominent ridge 

 near distal end; fingers gaping narrowly, largest 

 tooth at middle of immovable finger. Walking 

 legs rather narrow, meri with a superior subdistal 

 spine; third pair of legs over twice as long as 

 carapace. 



Abdomen of male broadly triangular; telson 

 much narrower than sixth segment. 



Measuretnents. — Carapace : male, length, 18 

 mm., width, 20 mm.; female, length, 20 mm., 

 width, 23 mm. 



Color. — Brown varying toward olive. 



Habitat. — Found actively crawling about on 

 wharves and stone jetties or resting in shallow 

 burrows above tidemark along the shores. The 

 crabs have often been found on vessels along the 

 coast hiding anywhere out of sight or reach and 

 coming forth at night to feed. 



Type locality. — u La Caroline.'''' 



Known range. — Magothy River, Chesapeake 

 Bay, Md., to British Honduras; West Indies to 

 Venezuela. 



Remarks. — This species is abundant where it 

 occurs in the Carolinas. Oviirerous females occur 



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