157 



punctate, when seen under the lens, and there is not a trace of pubescence. The dentation of 

 the marg-ins agrees quite well with Miers' figure, specially with his figure la, which presents 

 the anterior part of the cephalothorax in ventral view. The meropodite of the cheliped is armed 

 with an obsolete tooth near the distal end of the superior margin, the inner angle of the wrist 

 strongly prominent, the palm perfectly smooth, minutely punctate, at least in the adult (in the 

 young cf the palms are closely studded with small, sharp granules); the chelae are unequal, 

 the right being the larger; in the larger chela the palm is higher, the fingers are shorter and 

 more strongly toothed than in the left; in both chelae the fingers are longitudinally grooved; 

 the mobile finger of the right bears a strong, obtuse tooth, curved backward, near the base 

 of the inner margin. In the adult cf of Stat. 139 the fingers retain still a light-brown colour, 

 like that of the cornea, and the propodites of the ambulatory legs are clad with a short fur, 

 wrapped all round, and e.xtending on to the dactyli ; in the second adult and in the young the 

 fingers are nearly or wholly colourless, the two last joints of the walking legs are much 

 less hairy. 



The largest cf of .Stat. 139 has a greatest width of carapace (between tips of posterior 

 epibranchial teeth) of 15.5 mm. and a length of 11.75 miii., the (f of .Stat. 267 is very slightly 

 smaller, and the young specimen of Stat. 266 is only 5 mm. broad and 4.5 mm. long. This 

 last specimen was found on a deep sea Sponge (a Hexactinellid) ; perhaps in youth the species 

 leads a commensalistic e.xistence. 



The only "Challenger" specimen was dredged near the Fiji Islands, from a depth of 

 3 1 5 fathoms and was of about the size of my adult individuals. 



Eucrate de Haan. 



1835. Eucrate de Haan. Faun. Japon., Crust., p. 36. 



1858. Heteroplax Stimpson. Proc. Ac. Nat. Sc. Philadelphia, 1858, p. 94. 



1903. Platyoziiis Borradaile. Faun, and Geogr. Maldive and Laccadive Arch., v. i, p. 243. 



In the fronto-orbital breadth not being much less than the greatest width of the carapace, 

 the genus, with Pilumnoplax, differs from Carcinoplax and it allies {Catoptrus^ Libystes), but 

 it is distinguished among all others by the basal (or rather second) joint of the antennae 

 excluding itself from the orbit by means of an acute process at its antero-external angle, which 

 process is in contact with the inner suborbital lobe, and with the external angle of the front. 



The anterior margin of the front is straight, slightly notched in the middle ; the antero- 

 lateral margins of the carapace are short and usually armed with four depressed, blunt teeth ; 

 the dactyli of the walking legs are long, .slender and unarmed, those of the last pair are shorter, 

 much depressed, spiny along the margins and wholly straight. 



The genus Heteroplax with two species is very little known, but Stimpson expressly 

 states the excluding of the antennae from the orbits; for this reason de Man ^) placed the 

 genus near Eucrate and Alcock -) afterwards considered it identical with de Haan's genus. 



i) Journ. Linn, Soc. London, v. 22, 188S, p. 89. 

 2) L. c, p. 298. " 



SIBOr.A-EXPEliITIE XXXlXi''. 



