368 CRUSTACEA. 



lous. The last abdominal segment in the male is hardly longer than 

 its breadth at base, has a broadly rounded apex, and is about half as 

 broad as the penult segment. 



H. crassa, Dana, Proc. Acad. Nat. Sci. Philad., 1851, v. 252. 



Subfamily III. PLAGUSINiE. 

 Genus PLAGUSIA. 



De Haan, besides separating the genus Acanthopus from the old 

 Plagusige, makes two genera of the remainder; one, Plagtma (corre- 

 sponding to P. squamosa of authors), having a nagellum terminating the 

 palpus of the outer maxillipeds, and the other, Pliilyra (corresponding 

 to Plagusia depressa), having no nagellum to this palpus. The name 

 Philyra was earlier used by Leach for a genus of Oxystomes ; more- 

 over, we are not satisfied that the character mentioned, is in this case 

 of sufficient importance to require the separation into two genera. 



1. Articulus pedum 8 posticorum Btius non multispinosus. 



Plagusia squamosa (Serbst), Lamarck. 

 Island of Madeira. 



Length of carapax of a male, eighteen and three-fourths lines; 

 greatest breadth, nineteen lines; length of a female, eighteen and one- 

 fourth lines ; breadth, nineteen lines. 



In the areolation of this species the normal areolets may be dis- 

 tinguished. In the medial region the intramedial and extramedial 

 areolets are distinct ; the prsemedial, which is not separated from the 

 extramedial, terminates in a point or short spine on the front'either 

 side of the medial line. The posterior part of the intramedial areolet 

 is arcuate or angulate either side. Of the four lateral teeth, the pos- 

 terior is S, and the first probably includes D and E, as numerous 

 species in other groups exemplify; the second and third will then be 

 N and T. Of the anterolateral areolets, 6 L is distinct, but the others. 



