18 



G. 0. SAKS. 



[No. 8. 



in taking any of the diminutive males, and as, after a few days, 

 from some unknown cause, a sudden mortality occurred in this 

 aquary, affecting all the Cladocera therein, every chance of 

 securing the male of this species for examination was lost. 



True, I have not been able to find in the mud sent me 

 winter-eggs of the fore-described form — a fact easily accounted 

 for by their not being enclosed within any true ephippium;. — 

 but as to this species having been veritably raised from the 

 mud, I can testify from another observation, detecting, as I did, 

 easily determinable remains (antennæ and parts of the carapace) 

 of the same form in the ventricles of certain small fresh-water 

 fishes caught in the lake from which the mud was derived, and 

 kindly forwarded to our University Museum by Mr. Lumholtz. 



Family: — Daphnidæ. 



2. Daphnia LumhoUzii, n. sp. 

 (Pl. 1, figs. 1—10, Pl. 3, 4). 



Specific Character. — Female: — Head defined from 

 carapace by a distinct dorsal impression, and jutting out anteri- 

 orly as a very large lanceolate prolation pointing obliquely down- 

 ward (in some cases however much reduced in size) ; frontal mar- 

 gin straight or slightly arched; rostrum distinctly projecting; 

 fornix very prominent and exserted on either side to an acute, 

 spiniform point. Carapace (lateral aspect) broadly oval, free 

 edges of valves evenly curved, and armed with unusually elongate 

 and distant denticles. Spine of carapace exceedingly strong and 

 elongate, pointing obliquely upward. Eye rather large, with 

 numerous refracting corpuscles; ocular spot exceedingly minute. 

 Antennulæ small, but distinctly projecting. Tail with terminal 

 part gradually tapering, dorsal margin almost straight and armed 

 with comparatively small and well-nigh uniform denticles ; apical 

 claws without any secondary teeth at base. Ephippium having 

 the hinge produced both anteriorly and posteriorly, and with 

 obliquely disposed ampullæ. 



Male: — Head somewhat depressed, not prolonged anteri- 



