CANCROIDEA. 265 



Front very minutely denticulate, not sinuous. Anterior feet unequal, 

 hand externally near base pubescent, carpus armed on the inner 

 side with two spines, third joint having four slender teeth near the 

 inner apical margin. Posterior feet of moderate length, third joint 

 rather narrow. 



Plate 16, fig. 4 a, carapax, enlarged; b, outline of arm and carpus; 

 c, part of hand. 



Island of Tongatabu, Pacific Ocean. 



Length of carapax, two lines ; breadth, two and a half lines. Co- 

 lour pale, with the anterior border brownish black. 



NOTE. The Trapezia digitalis (M. Edwards's Crust., i. 429) evidently 

 belongs to this genus, and it is distinguished from the others here 

 described, by having the front armed at middle with two small pointed 

 teeth, and elsewhere finely denticulate. The T. leucodactyla of Riip- 

 pell (loc. cit., p. 28), has not the side tooth, as is usual in the Tetra- 

 lise, but the characters mentioned do not suffice to determine that it 

 is a true Tetralia. 



GENUS QUADRELLA. 



Carapax convexus, Icevis, subquadratus, margine laterali fere longitudi- 

 nali, /route lato, Jiorizontali, bene spinoso, oculis ad angulos insitis. 

 Articulus antennas, externce Imus perbrevis, secundo non longior, ad 

 frontem non attingens, margine orbitce 7iiatu carente exclusus. Pedes 

 longi, posteriores graciles, tarsis unguiculatis. 



Carapax convex, smooth, nearly square, sides nearly longitudinal ; 

 front broad, horizontal, regularly spinous, eyes at the angles of the 

 carapax. First joint of outer antennae, very short, not longer than 

 second, not reaching to front, excluded from margin of orbit, there 

 being no hiatus. Feet long, the posterior quite slender, tarsi ungui- 

 culate. 



Near Trapezia, but the carapax is convex, the front has six pro- 



67 



