CANCROIDEA. 285 



f. 2), but according to Edwards (Crust., i. 461), that species, besides 

 having the fourth lateral tooth rudimentary, has the third tooth but 

 little salient ; while in our species the latter is quite as prominent as 

 the second, and these two are the largest ; also, the external frontal 

 teeth are pointed and small, while they are rounded or subtruncate 

 in the crassimana. It is also near the Thalamita cceruleipes of Hom- 

 bron and Jacquinot (Crust., Voy. au Pole Sud, PI. 5, f. 6), but that 

 has the fourth lateral tooth much larger than in the above, although 

 still a little shorter than the rest, and the peduncle of the eye is set 

 around with short spines or processes, while in the above, there are 

 no projecting points ; the hand also is much less stout. The small 

 tubercles of the hand are scattered over the upper and lateral surface, 

 as far down as the first costa. The under and lower half of inner 

 surface of the hand is smooth. The posterior natatory legs are smaller 

 than usual in this genus. 



GENUS CHARYBDIS. 



Carapax angmtior. Frons dimidio latitudinis brevior, et margo antero- 

 lateralis obliquus. Articulus antennae externce \miis minus oblongus, 

 articulo sequente a Jiiatu orbitce paulum remoto. 



Carapax narrower than in TJwlamita. Front shorter than half the 

 breadth of carapax, and antero-lateral margin oblique. First joint 

 of outer antennje less oblong, and the following joint much less dis- 

 tant from the orbit. 



CHARYBDIS ORIENTALIS. 



Carapax Icevis, regione mediand 2 3-Zmeis elevatis intersectd, fronie 

 arcuato, dentibus valde obtusis, Stio triangulate, margine antero-late- 

 rali 6-dentato, dentibus acutis, 2do minimo, postremo non longiore. 



Carapax smooth, median region crossed by two or three raised lines, 

 front arcuate, teeth very obtuse, third triangular, antero-lateral 

 margin six-toothed, teeth acute, second very small, last not longer 

 than others. 



Plate 17, fig. 10, carapax, natural size. 



72 



