:y/ 



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

 the martrins agrees quite well with Miers' hgure, specially with bis figure 2a, wbich presents 

 the anterior part of the cepbalothorax 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 

 strono-ly prominent, the palm perfectly smooth, minutely punctate, at least in the adult fin the 

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

 the rio^ht being the larger; in the larger chela the palm is higher, the hngers 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 c? 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 

 fineers are nearlv or whollv colourless, the two last joints of the walking legs are much 

 less hairy. 



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

 epibranchial teeth) of 15.5 mm. and a length of 11.75 'nni-. the cf 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 exi-stence. 



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. PlatyorAiis 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 Pibiuinoplax, difters from Carcinoplax and it allies [Cafoptrus, Lièystes), 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. 



1) Journ. Linn. Soc. London, v. 22, 1S88, p. 89. 



2) L. c, p. 298. 



SIBOGA-EXPEIUTIE XXXlX<r'. 



