CRUSTACEA OF TUE MERGTJI ABCHIPELAGO. 31 



Genus Med^us, Dana. 



20. Med^us distinguekdus, de Haan. 



Caucer (Xantlio) distinguendus, de Haan, Fauna Japonica, Crustacea, 

 p. 48, tab. xiii. fig. 7- 



Chlorodius distinguendus, Stimpson, I. c. p. 32. 



Xantho distinguendus. Heller, Beitrdge zur Crust aceen-Fauna des rothen 

 Meeres, Sitzungsher. k. Acad. Wiss. Wien, Bd. xliii. 1861, p. 323. 



Eleven specimens (6 c? , 5 $ ) were collected, eight at Elpbin- 

 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 Xantlio 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 o£ 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 magnify ing-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 Xantlio distinguendus to the genus Medceus, 

 because it agrees perfectly in its physiognomy and outer appear- 

 ance with the other representatives of the genus, as, e.g., Medceus 

 elegans, Alph. M.-Edw. One of the specimens is infested by a 

 Bopyrid. 



Dimensions of the largest specimen ( c? ) : — 



millim. 

 i 

 3 



Distance between the last antero-lateral teeth . . 19^ 

 Length of the cephalothorax, the basal portion 

 of the abdomen not being included 13 



Medceus disfitiguendus, de Haan, has previously been recorded 



