FISHERY BULLETIN; VOL. 86, NO. 2 



Fracture Zone (see: Kong et al. [19851; Leg 106 

 Shipboard Scientific Party 1 19861; Ocean Drilling 

 Program Leg 106 Scientific Party [1986]), 

 23°22.09'N, 44°57.12'W, 3,437 m, Aluin Dive 

 1683, MARK vent, Stn. 1, scoop, 30 May 1986, 

 pilot D. Foster, observers S. Humphris and J. Ed- 

 mond. From NSF-Leg 106-Ocean Drilling Pro- 

 gram, NSF Grant OEC-8311201 to J. F. Grassle, 

 Woods Hole Oceanographic Institution, Woods 

 Hole, MA. 



Measurements in mm. — 



Description. — General aspect similar to that of 

 B. thermydron, cancroid, depressed. Carapace 



(Figs. 9, lOd) broad, transversely elliptical, its 

 rounded lateral angles displaced somewhat ante- 

 riorly; almost flat in middle dorsally, very 

 slightly arched from anterior to posterior and 

 near lateral margins; anterolateral region pro- 

 duced, margin not toothed; surface finely granu- 

 late anteriorly and laterally, smooth but 

 minutely punctate to unaided eye over posterior 

 2/3 to 3/4; regions indistinct. Frontoorbital width 

 ca 1/3 carapace width. 



Front almost evenly rounded and somewhat de- 

 flexed, projecting over folded antennules, shallow 

 median depression continued onto protogastric 

 region giving faint suggestion of bilobation; mar- 

 gin beaded with line of fairly uniform granules, 

 closely packed on anterior and anterolateral parts 

 but diminishing almost to obsolescence near or- 

 bits. Arcuate tract of scattered punctations 

 sweeping across anterolateral, hepatic, orbital, 

 protogastric, and metagastric regions. Trans- 

 verse tract of rather prominent granules at rear 

 edge of protogastric region. Carapace with 

 smooth part behind these anterior areas micro- 

 scopically granular and punctate anteriorly, 

 grading posteriorly into almost featureless sur- 



FlGURE 9. — Bythograea mesatlantica , holotype 9: dorsal. Scale = 3 mm. 



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