72 G. o. sars. [No. 8, 



spine of the outer edge located close to the apex. The ter- 

 minal claw, finally, is quite regularly curved, not as in the pre- 

 ceding species sigmoid. The left leg, as usual, is much shorter 

 than the right and has the inner ramus rather small and of 

 simple conical form. The outer ramus is less complicate in 

 structure than that of the male of D. orientalis, exhibiting at 

 the end two slightly projecting angles, between which a small 

 seta is attached; but of the peculiar ciliated lamella found in 

 the preceding species, no trace can be detected. 



Biological Observations. — Of this elegant species 2 speci- 

 mens, male and female, were observed in the first days of July 

 1884 in one of my aquaries, a rather small glass-vessel, prepared 

 with mud from the Gracemere Lagoon sent by Mr. Lumholtz. 

 On the 9th July the female specimen was fished up by the aid 

 of a dipping tube and submitted to a closer examination, a 

 coloured drawing being made from life. It was then provided 

 with a large egg-bag containing numerous pale greenish ova, 

 and on removing the bag two spermatophores were besides found 

 adhering to the genital orifice (see fig. 5). The male specimen 

 I then failed to catch on account of its exceedingly rapid 

 movements, and some days later it was no more to be found. 

 As no other specimens of this form appeared subsequently, i* 

 seemed that my anatomical investigations of this species, restricted 

 as they were only to the female sex, should remain incom- 

 plete. On examining, however, some time later, the stomachal 

 contents of some small fresh water fishes caught in the same 

 Lagoon and sent to our Museum, I fortunately detected numer- 

 ous remains of this form, comprising both females and males- 

 A few of the male specimens were even in a comparatively 

 well preserved condition, so as to allow a rather complete dis- 

 section and examination of the several limbs, whereby ^ 

 specific differences could be ascertained also as regards the m» le 

 sex. The figures 11 and 12 here given have been made from 

 such dissections. 



In habits the species perfectly agrees with the preceding 

 though the animal is perhaps still more active in its movements. 



