CANCROIDEA. 



281 



T. crucifera), Charybdis (for T. natator and allied, the hexagonal 

 species), and Thalamita (for the quadrilateral species). Oceanus does 

 not, in our opinion, differ sufficiently from Charybdis to be sustained. 



1. Frons subinteger* 



Thalamita admete (Herbst). 



Plate 17, fig. 5 a, outline of front, and of crest of base of outer an- 

 tennas, from Sandwich Islands ; b, outer view of hand ; c, summit of 

 inner branch of first maxillipeds. 



Sandwich Islands, Samoan Islands, and Wakes Island, Pacific 

 Ocean ; also Sooloo Sea, East Indies. 



Length of carapax of a small specimen from Upolu, of the Samoan 

 Group, six and three-fourths lines ; breadth, eleven and one-fourth 

 lines ; ratio of length to breadth, 1:1-66. The crest of the base of the 

 outer antennas is evenly and short denticulate. The front is straight 

 transverse and not arcuate. The medial region is crossed at middle 

 by a strong line, and anteriorly either side there is a short line pa- 

 rallel ; posteriorly another, which reaches to the posterior tooth either 

 side. Although generally but four lateral teeth are present, a minute 

 fifth between the third and fourth is sometimes seen. 



Cancer admetus, Herbst, pi. 57, f. 1. 



Portunus admete, Latreille, Nouv. Diet. d'Hist. Nat., xxviii. 44. 



Thalamita admete, Latr., Reg. Anim., iv. 33 ; Edwards, Crust., i. 459. 



Thalamita Integra. 



Carapax convexior, gldber, nitidus, regione mediand Uneis elevatis non 

 intersectd, fronte paulo arcuato, lobo preeorbitali longo et inarginem 

 recto, et paululo elevato, margine antero-laterali b-dentato, dentibus 

 acutis, 4:to rninuto. Articulus antennce external lmus prazlongus, 

 cristd longd Integra. Pedes antici breves, manu nitidd, omnino lawi, 

 extas non costatd, supernh breviter 2>-spinosd {spina wad in margine 



71 



