Descriptions of some Australian Pliyllopoda. 15 



with only 4 or 5 lines of growth; the dorsal edge straighter, 

 less curved than in Limnadia; 18 pairs of feet. The head 

 and antennæ do not differ essentially, but the gills are much 

 larger than in Limnadia, while the upper or dorsal lobe of 

 the flabellum is much smaller than in Limnadia.» 



Besides the 2 American species E. Agassim and E. tex- 

 ana, he refers to this genus Limnadia stanleyana, King, and 

 Limnadia antillarum, Baird. 



Remarks. The difference from Limnadia in the form and 

 sculpture of the shell, as recorded in the diagnosis given by 

 Prof. Packard, applies only to quite young specimens of 

 Limnadia stanleyana, but does not at all hold as regards 

 fully grown sjDCCimens. On the whole the greater or smaller 

 height of the shell and the number of lines of growth, are both 

 very unreliable characters, not even employable for defining 

 species, and much less so genera. For in the very same 

 species both the form of the shell and the number of lines of 

 growth will be found to change according to age, the shell 

 being, as a rule, much wider in adult than in young specimens, 

 and the lines of growth in fact increasing successively from 

 a single one to a very large number. Of the distinguishing 

 characters recorded by Prof. Packard, there thus only remain 

 the two following: The somewhat smaller number of legs, and 

 the different proportion between the epipodite (gill) and the 

 upper lobe of the exopodite (flabellum). In the first of these 

 characters L. stanleyana agrees with the other species of the 

 genus Eulimadia; in the latter this species forms, as it were, 

 a transition between the two genera. The validity of the 

 genus Eidimadia would therefore seem to be somewhat question- 

 able. There is, however, at least one feature by which the 

 species of the present genus seem to differ very markedly 

 from those of Limnadia. Whereas the latter, as stated both 

 by other authors and by myself, are unisexual, or exclusively 

 parthenogenetical, those of Eulimadia are pronouncedly bisexual, 



