16 G. O. Sars. 



maie specimens being fully as frequent as females. Moreover 

 the covering of the eggs is somewhat different in the two 

 genera. 



Besides the 4 species recorded by Prof. Packard, a 5th 

 has been added by Prof. Brady from South Australia under 

 the name of E. rivolensis, and the Limnadia sordida of King, 

 if in reality distinct from E. stanleyana, ought also undoubtedly 

 to be included in this genus. 



2. Eulimadia stanleyana, King. 



(PL 2 & 3). 



Limnadia stanleyana, King, On Australian Entomostra- 

 cans. Proc. Roy. Soc, Y. Diemen^s Land, 1855, p. 70. 



Limnadia stanleyana, Claus, «üeber den Körperbau einer 

 australischen Limnadia und über das Manchen derselben.» 

 Zeitschr. f. wissensch. Zoologie, Bd. 22, 1872, p. 355, PI. 

 XXIX & XXX. 



Syn. ? Esthcria compressa, Baird. 



Specific Characters. Shell much compressed and, seen 

 from the side, in fully grown females, subtrianglar in form, 

 umbones very prominent and occurring much nearer the 

 anterior than posterior extremity, dorsal margin obliquely 

 declining, ventral margin strongly curved in the middle, anterior 

 extremity short, rounded, posterior rather produced and obtusely 

 truncated at the tip; shell in young specimens more regularly 

 oval or elliptical in form, with the umbones not at all project- 

 ing. Shell in adult male much narrower than in female, seen 

 from the side, oblong oval in form, umbones not very promi- 

 nent, dorsal margin nearly horizontal, posterior extremity 

 broadly expanded. Valves rather thin, and provided in fully 

 grown specimens with numerous lines of growth, in youug 

 ones, as usual, with a much smaller number of such lines. 



