1885.] 



CLADOCERA. 



21 



behind the rostrum. They are provided at the apex with a 

 bunch of minute, clear, sensory papillæ, besides a single delicate 

 bristle. 



The antennæ agree in all essential characters with those 

 of other Daphniæ, being comparatively feeble in structure. The 

 natatory setæ are rather elongate, and have no pigmentary spot 

 at the base of the terminal joint. 



The oral parts and the branchial legs would not seem to 

 exhibit any marked difference from what is known to charac- 

 terize other species of the genus. 



The tail (fig. 3) is provided with 4 well-marked dorsal 

 processes, the two anterior of which are very large and not 

 connate at the base. The terminal section tapers evenly toward 

 the apex, the dorsal margin being almost straight. The anal 

 denticles, about 12 on either side, occur comparatively small and 

 well-nigh uniform in size. The apical claws are gently curved, 

 and do not exhibit the slightest trace of secondary teeth at the 

 base, whereas a very delicate ciliation may be traced along their 

 sides well-nigh to the tip. The caudal setæ are rather short and 

 of the usual structure. 



The inner organs, which, in the living animal, admit of being 

 traced with great distinctness through the transparent integu- 

 ments, would seem to agree in all essential characters with 

 those of other Daphniæ. The arrangement of the dorsal muscles 

 moving the antennæ, is almost precisely as in D. magna Strauss, 

 and somewhat dissimilar from that in other species of the genus, 

 the median being quite narrow and placed in close approximation 

 to the posterior muscle. 



The eggs, when recently deposited in the matrix from the 

 ovaries (see fig. 1), are almost globular in shape and furnished 

 with a large central oil-globule, of a light, yellowish colour; the 

 yolk-mass is of a clear bluish-green. 



The above-given description has been worked up from indi- 

 viduals domesticated in my aquaries during the summer-months. 



