ENTOMOSTRACA OF MINNESOTA. 149 



The species of Ikiphnella found about Minneapolis, occasionally 

 abundant, seems not to differ in any important character from Euro- 

 pean types of i). brachyiira, although I formerly regarded it as distinct 

 (D. tvinchelU, Microscopic Entom., Addenda). 



Head less than one-half the body (about 0.27 mm., while the body 

 is 0.6 mm. long); eye about one- fourth head; antennae when refiexed 

 extend a little beyond two thirds the length of the body. Male, 0.7 

 mm. long; antenntc reflexed, reaching base of shell; anterior antennae 

 extremely long; copulating organs reaching nearly to end of claws. 

 Having carefully compared our specimens wuth the descriptions and 

 figures given by Birge for his D. exiyinosa, the evidence seems to indi- 

 cate not only that they are identical, but both are really D. brachyura. 

 The distinctive characters of D. expinosa are a greater indentation be- 

 tween head and body, absence of caudal teeth, greater length of male 

 appendages, and the openingof the vasadeferentia below the "instep" 

 of these appendages. 



The absence of teeth upon the post-abdomen is of even generic im- 

 portance according to Sars, who gives it in his synopsis of genera as 

 typical for JJaplmeUa. In our specimens the claws are at least pecti- 

 nate if not serrate, while the appendages of the male reach generally 

 nearly to the middle of the claws. The relative length of these ap- 

 pendages and the antennee of the male is variable. 



Daphnella braudtiaua Fischer. 



Plate XXXVII, Figs. 3-6. 



Head as long as half the body, antennae when refiexed reaching 

 beyond the posterior margin of the valves. Length 0.8 mm. Of the 

 validity of this species we can foim no conclusion. It is usually con- 

 sidered a variety or phase of the above. 



Daphnella excisa Sars. 

 Sars '85 (Diaphanosoma excisum). 



Similar to D. brachyura. Head obtusely truncate cephWad, with- 

 out distinct sinus beneath the eye, dorsal margin slightly arched. 

 Carapace oblong, truncate posteriorly with the dorsal angle nearly a 

 right angle, valves inflected in the middle and wide open posteriorly, 

 having awellmaiked angular emargination at the junction of the 

 ventral and caudal margins. Eye large. Antennae, when reflexed, 

 not reaching the caudal margin of shell. Length 1.30 mm. The head 

 occupies about one-third the entire length. The apical claws are 

 armed with three teeth. 



