THE AJrPlIIPODA AND CLADOCEEA. 41 



this species, except tbat in the fifth perseopods the fifth joint is not shorter but longer 

 than the sixth. It does not help to decide the question, which Glaus himself leaves 

 doubtful, as to whether his mecUterraueus should be regarded as a synonym of his earlier- 

 named globiceps. Norman may very well be right in considering it to be the young 

 of B. crusculum, Bate. 



Occurrence : 31 b. 50 to fathoms. 1 specimen. 



23. Brachysceltjs sp. 



The collection contains a representative of this genus only 2 mm. in length. The 

 branches of the pleopods are four-jointed and the mouth-organs extremely delicate. It 

 is much smaller than any species hitherto described, and, though aU the limbs are well 

 developed, the probability remains that it may be a young form of a species already 

 named — such, for example, as B. globiceps or B. vtiediterraneus (Glaus). The third 

 perseopods have the second joint elongate-oval, with two spinules on the front margin, 

 which is decidedly convex. The second joint is much more broadly oval in the fourth 

 pair, and. less narrowed below than in many species ; the fifth and sixth joints have the 

 usual serration of the front margin. The fifth perteopods have the second joint like that 

 in the ' Ghallenger ' species, B. B avail U, long and narrow, much wider above than below. 

 Here, however, the remaining joints are differently proportioned, increasing in length 

 from the third to the sixth, these with the minute finger together about equalling the 

 length of the second joint. The telson is broad, apically subacute, not reaching so far 

 back as the outer branch of the third uropods, which is considerably shorter than the inner 

 branch. A rather larger specimen and one only about 1 mm. long were also obtained. 



Supposing these forms to be juvenile, it should be noticed that there is no 

 reminiscence of the strange character described by Bate for the fourth perieopods of the 

 larval B. crusculum. 



Occurrences : 2^g. fathoms. 1 specimen, 1 mm. long. 

 21 e. fathoms. 1 sj^ecimen, 2 mm. long. 

 33 d. 100 to fathoms. 1 specimen, 2"5 mm. long. 



ENTOMOSTRAGA.— Section Branchiopoda. 

 CLADOCERA. 

 Tribe ONYCHOPODA. 

 Fam. POLYPHEMIDiE. 



EvADNE, Lov^n, 1836. 



1836. Evadne, Loven, K. Vet.-Akad. Ilandlingar (Stockholm) for 1835, p. 1. 



1902. Evadne, Sars, On the Polyphemidae of the Caspian Sea, Ann. Mus. Zool. Acad. Imp. Sci. 

 St.-Petersbourg, vol. vii. p. 10 (extract). 



The earliest and one of the latest references to this AveU-known genus will suffice for 

 the present purpose. Sars remarks that it is very abundantly represented in the 

 Caspian Sea, " whereas in the Oceans hitherto only three very sharply defined species 



