Fresh-water Entomostraca of South America. 51 



occurs, in the present species 2 distinctly separated digitiform 

 appendages are found, much as in the species of the genus 

 Leydigia. 



I have much pleasure in dedicating this handsome species 

 to the distinguished zoologist Dr. H. v. Ihering, to whom I 

 am indebted for the material upon which this paper is based. 



Occurrence. — Several specimens of this form were 

 occasionally taken up in the dipping-tube from the bottom 

 of some of my aquaria prepared with mud from S«o Paulo. 

 In habits it exactly agrees with the other species of this 

 genus. 



20. Alona guttata, G. O. Sars. 



(PI. IX, figs. 3, 3 a). 



Alona guttata, G. 0. Sars, Om de i Omegnen af Christiania fore- 

 kommende Cladoeerer. Chr. Vid. Selsk. Forhandl. 1861, p. 39. 

 Syn. Alona parvula Kurz. 

 » » tuberculata Kurz. 



Remarks. — I now fully concur with Prof. Lillje- 

 borg in believing that the 2 species established by Kurz 

 as A. parvula and A. tuberculata ought only to be con- 

 sidered as varieties of the species previously described by 

 the present author as A. guttata. I have, indeed, on ex- 

 amining the specimens developing in my aquaria, been en- 

 abled to prove that the peculiar tuberculated structure of 

 the shell at first observed in this form is subject to great 

 variation. At a certain period, almost all the specimens 

 exhibited the tubercles of the shell very distinctly; but sub- 

 sequently this peculiar structure gradually became effaced, 

 and at last many specimens only exhibited the faint reticu- 

 lation indicated by Kurz in his A. parvula. One of these 

 specimens is figured in the accompanying plate, together 



