FKESHWATER CRUSTACEA OE TASMANIA. 87 



Boeckella uobusta, Sars, Arcliiv for Math, og Naturvid. xviii. 



This large and handsome species was found in great abundance in several small 

 muddy ponds near Hobart (in a pond near the road at Sandy Bay and in a small pond 

 near the Cascade Brewery). Sars describes it from the neighbourhood of Sydney, so 

 that it is evidently a widely distributed form in Southern Australia. It can at once be 

 distinguished from the other species by its great size, by the comparative shortness of 

 the setae on the uropods, by its pale livid colour, and by the great length of the lateral 

 projections on the fifth segment. 



Genus Brunella, gen. n. 



I have made this new genus of the Diaptomidae to include a species found in a large 

 weedy freshwater lagoon near Adventure Bay, Bruni Island. It was present in great 

 quantities, but I did not meet with it anywhere else. It is impossible to include it in 

 any existing genus, as the structure of the thoracic limbs, and especially of the fifth pair 

 in the male, is quite peculiar. In its other characters (e. g. structure of antennae and 

 mouth-parts) it agrees very well with Diaptomus or Boeckella. 



The diagnostic characters which concern the thoracic limbs are: — 



1. The first thoracic limb has the external ramus Particulate and the internal 



ramus uniarticulate (PI. 18. fig. 12). 



2. The second, third, and fourth limbs have the external ramus triarticulate and 



the internal ramus biarticulate (PI. 18. fig. 13). 



3. The fifth thoracic limbs in the male differ on the risdit and left side. The risrht 



limb has the external ramus 2-jointed, the last joint being spatulate and 

 carrying a very small terminal spine ; the internal ramus of this limb is 

 2-jointed with an extra internal lobe. The left limb has the external ramus 

 3-jointed and ending in a greatly elongated claw; the internal ramus of this 

 limb is 3-jointed (PL 18. figs. 15 & 16). 



4. The fifth thoracic limbs of the female have the external ramus 3-jointed and the 



internal ramus 2-jointed (PL 18. fig. 14). 

 This combination of characters is very peculiar. Thus the first two characters point 

 to affinities with Eurytemora, but the character no. 4 is unparalleled in any freshwater 

 Diaptomid, and one has to go to some marine genus (e. g. Centropages) for comparison. 

 Character 3 shows some agreement with Parabroteas michaelseni, described by Mrazek 

 from S. America, but in its other characters it differs widely from that genus. 



Brunella tasmanica, sp. n. (PL 18. figs. 6-16.) 



Female. — The fore-body is narrow and cylindrical ; the head-segment tapers anteriorly 

 and has a slight depression laterally near the anterior end ; this segment exceeds in 

 length the two following segments. 



The fifth segment has small lateral projections, which are bilobed, the external lobe 

 being the larger and rounded at the end ; the internal lobe is small and more acute. 

 The first abdominal segment is rather tumid ; the abdomen has three distinct segments, 

 not counting the segmented bases of the uropods. 



12* 



