Fresh-water Entoniostraca of South America. 73 



Occurrence. — The aquaria in which this form 

 developed, were prepared with mud, partly from Itatiba, 

 partly from Argentina. 



Gen. Dadaya^ n. 



Generic Characters. — Carapace not very tumid, 

 of rounded oval shape, with the upper margin more curved 

 than the lower, and the infero-posteal corners unarmed. 

 Head large and procumbent, terminating in a comparatively 

 short triangular rostrum. Shell-sculpture reticulate. Both 

 eye and ocellus of extraordinary size. Antennulæ slender, 

 projecting far beyond the tip of the rostrum. Antennæ nor- 

 mal. Lip-plate large, acuminate. Caudal part rather broad, 

 lamellar, lower corner not projecting; no lateral denticles 

 present. Male unknown. 



Remarks. — This new genus is founded upon the 

 remarkable form recorded by Mr. E. Daday from Ceylon 

 under the name of Mona macrops. It is evident, that this 

 form is not a true Alona, nor can it in my opinion be re- 

 ferred to any of the other known Lynceid genera, for which 

 reason I have felt justified in establishing a new genus, 

 for its reception, which I have much pleasure in naming in 

 honour of the distinguished Hungarian naturalist, Dr. E. 

 Daday, to whom we are indebted for several excellent papers 

 on these little animals. I regret that, owing to want of suf- 

 ficient material, I have not been able to examine the struc- 

 ture of the legs more closely, nor that of the still un- 

 known male. 



