(Ns 
CRUSTACEA OF THE MERGUI ARCHIPELAGO. 31 
Genus Mepzus, Dana. 
20. MEDAUS DISTINGUENDUS, de Haan. 
Cancer (Xantho) distinguendus, de Haan, Fauna Japonica, Crustacea, 
p. 48, tab. xiii. fig. 7. 
Chlorodius distinguendus, Stimpson, l.'c. p. 32. 
Xantho distinguendus, Heller, Beitrdge zur Crustaceen-Fauna des rothen 
Meeres, Sitzungsber. k. Acad. Wiss. Wien, Bd. xlii. 1861, p. 323. 
Eleven specimens (6 3, 5 2) were collected, eight at Elphin- 
stone Island and three at King Island Bay. 
These specimens, which are doubtless very young, agree so 
well with the description and the figure of Xantho distinguendus 
in the ‘ Fauna Japonica,’ that I have no hesitation in regarding 
them as identical with it. They seem only to differ a little from 
the Japanese specimens in the meropodites of the ambulatory 
legs being less distinctly granulated, and in the upper margin of 
these joints being slightly carinate. 
I have little else to add to the existing description, this 
species having been well figured by de Haan. The postero- 
lateral sides of the carapace are distinctly granulate, the 
cardiac region appears smooth to the naked eye, but minutely 
granulate and punctate when it is seen under a magnifying-glass. 
The penultimate joint of the male abdomen is nearly quadrate, 
with the lateral margins slightly concave. 
Stimpson was in error in referring this species to the genus 
Chlorodius, and in supposing it to be probably a variety ot 
Leptodius exaratus, the fingers of the anterior legs being pointed 
and not at all excavated. Leptodius exaratus, moreover, is a 
quite different species. 
I refer de Haan’s Xantho distinguendus to the genus Medeus, 
because it agrees perfectly in its physiognomy and outer appear- 
ance with the other representatives of the genus, as, e. g., Medeus 
elegans, Alph. M.-Edw. One of the specimens is infested by a 
Bopyrid. 
Dimensions of the largest specimen ( ¢ ):— 
millim. 
Distance between the last antero-lateral teeth .. 194 
Length of the cephalothorax, the basal portion 
of the abdomen not being included .......... 13 
Medeus distinguendus, de Haan, has previously been recorded 
