100 GENUS PLAGUSIA. [October. 



world, concluded that he was approaching land, in con- 

 sequence of findintJ- this animai alive on some floating ma- 

 rine plants. To a specimen under examination a Spirorbis 

 is attached. 



Genus PLAGUSIA. Latr. 



Thorax a little narrowed before; anterior feet short; 

 mouth nearly closed; Intermediate antennae reflected iiito 

 two profound longitudinal fissures of 4:he front, which di- 

 vide the clypeus above. 



SPECIES, 



P. depressus. Thorax leprous, three-toothed on each 

 side; carpus with an impressed line above, and prominent, 

 emarginate, angle within. 



Inhabits Gulf- Stream. 



Grapsus depressus — Latr. Gen. Crust» et Ins. 



Cancer depressus of Authors. 



Cabinet of the Academy. 



Thorax with numerous distant punctures, and exhi- 

 biting the appearance of being covered with scales, each 

 of which is bounded before by a line of impressed points, 

 furnishing hairs; dorsal foramince^ rather large, oval, trans- 

 '^ verse, open; mouth closed; recipient grooves of the interior 

 antennse, terminating nearly in a line with the hind margin 

 of the orbits, separating the clypeus into three parts, of 

 which the intermediate division is largest, emarginate at tip, 



* Not knowing what term has been made use of by Naturalists to express 

 these parts, I have applied this for the present; they consist of two small aper- 

 tores situate near each otlier, transversely, about the middle of the thorax, just 

 before the abbreviated transverse line; they might furnish characters, drawn 

 from their form and relative -position; they are sometimes parallel, sometimes 

 oblique, round, oval, &c. 



