1889.] ON SOME FRESHWATER OSTRACODA AND COPEPODA. 71 



-extremely small and rudimentary, knob-shaped, and only provided 

 with a single apical spine. 



The body is in a living state of the animal highly pellucid 

 and almost colourless, with only a very faint bluish or greenish 

 tinge. The ova contained in the rather large egg-bag are also 

 of a much paler greenish hue than in the preceding species. 

 Within the anterior division of the body several rather large and 

 highly refracting oil-globules are seen rather regularly arranged. 

 Similar oil-glubules disposed in the same manner are also found 

 in the preceding species, but by far not so large and conspicu- 

 ous. Their destination would seem to be that of diminishing 

 the specific weight of the body and thus of facilitating the 

 swimming motions of the animal. 



Description of the male. — In its outer habitus the male 

 would seem to exhibit quite analogous differences from the female, 

 as described in the preceding species. 



The right anterior antenna (fig. 11.) exhibits the same 

 3 divisions, but the middle one is far less swollen, and both 

 this and the terminal section' are much more elongate than in 

 the male of D. orientalis. As in this species the antepenulti- 

 mate joint is produced at the end anteriorly to a spiniform, 

 slightly upturned process. 



The last pair of legs (fig. 12), though of a type quite 

 similar to those in the male of the preceding species, yet 

 exhibit well-marked differences in their details. Thus the 

 right leg is much more slender and has both rami rather 

 deviating in shape from those in the said species. The 

 inner ramus of this leg is relatively much larger, reaching con- 

 siderably beyond the 1st joint of the other ramus, and has the 

 form of an oblong lamella, somewhat expanded towards the end 

 and finely serrulate at the inner edge. The 1st joint of the 

 outer ramus is rather narrow, nearly twice as long as it is 

 °road and wants the spiniform outer corner found in the 

 Preceding species. The 2nd joint likewise is much more 

 ^nder, narrow oblong in form and nearly of uniform breadth 

 throughout. It is moreover somewhat incurved and has the 



