On Fresh-water Entomostraca. 25 



of the antennulæ, a very conspicuous, rounded prominence, 

 defined from the labrum by a deep notch. Eye compara- 

 tively larger than in that species. Antennulæ in female 

 comparatively much longer and narrower, sublinear in form; 

 those in male considerably exceeding half the length of the 

 body. First pair of legs in both sexes of a simular structure 

 to that in the preceding species. Terminal claws of tail 

 armed at the base with a well-marked, comb-like series of 

 secondary teeth. Ephippium with 2 transversely disposed 

 egg-ampullæ. Length of adult female 1,20 mm., of male 

 0,70 mm. 



Remarks. — Though very nearly allied to the preceding 

 species, as also to the European M. paradoxa, this form 

 may at once be distinguished from both of them by the 

 form of the head in the female, the remarkably elongated 

 and narrow antennulæ, and finally by the terminal claws of 

 the tail being distinctly denticulated at the base, like those 

 in M. brachiata. 



Description of the female. 



The length of the largest specimens is 1,20 mm., and 

 this form is accordingly but little inferior in size to the 

 preceding one. 



The general form of the body (see fig. 1) agrees rather 

 closely with that in M. australiensis. On a closer com- 

 parison, however, the head is found to differ very markedly 

 in shape, being quite evenly vaulted dorsally, without 

 exhibiting any trace of a sinus above the eye The front 

 is obtusely rounded and, as in the preceding species, but 

 little prominent. On the other hand, the inferior part of 

 the head is produced, at the insertion of the antennulæ, to a 

 rather conspicuous, rounded prominence, which is defined 



