30 DR. J. GQ. DE MAN ON THE PODOPHTHALMOUS 
Genus Euxanruus, Dana. 
18. Evxantuts Mamituatus, J-EHdw. 
Cancer mamillatus, Milne- Edwards, Hist. Nat. Crustacés, p. 376. 
Euxanthus mamillatus, Alph. Milne-Edwards, Nouv. Arch. du Muséum 
East. Nat. t. 1. p.292, pl. xvenie. 2, Sets 1x, pe go: 
Four specimens are in the Collection, two of which were col- 
lected at Owen Island and two at Elphinstone Island. 
I am inclined, with Milne-Edwards, to regard Husanthus 
melissa, Herbst, EL. nitidus, Dana, and EF. mamillatus, M.-Edw., as 
varieties of the same species. An adult male specimen, the 
cephalothorax of which is 82 millim. long and 49 millim. broad, 
wholly agrees with the description of true H. mamillatus, M.- 
Edw., but in younger specimens, about 21—24 millim. in breadth, 
the elevations of the upper surface of the carapace are some- 
what more rugose. I now suspect that in young specimens of 
these crabs the bosses are always a little rugose, and that they 
become nearly smooth in adult specimens of /. mamillatus, while 
they remain rugose and become even still more so in the form 
which has been described as H. Huonzi, Lucas. 
Euxanthus mamillatus has hitherto been recorded from the 
coast of Cochin China and from Australia. 
Genus XantuHo, Leach. 
19. XanrTHO IMPRESSUS, Lam. 
Cancer impressus, Lamarck, l. c. p. 272. 
Xantho impressus, Milne-Edwards, Hist. Nat. Crustacés, t. i. p. 393. 
Xantho impressus, Alph. Milne-Edwards, Crustacés de la Nouv. Calé- 
donie, Nouv. Arch. du Muséum Hist. Nat. t. ix. p. 198, pl. vi. fig. 2. 
One young male specimen was collected near Owen Island, 
the cephalothorax of which is 22 millim. long and 38 millim. 
broad. 
This very rare species has been collected also at Mauritius 
and on the shores of New Caledonia, so that we may conclude 
that it is distributed throughout the Indian Ocean and the 
Malayan archipelago. 
