86 ME. GEOFFREY WATKIN SMITH ON THE 



of 3 distinct segments, and also the uropods are rather distinctly segmented off, making 

 a fourth indistinct segment (PI. 17. fig. 14). 



The first antenna has 24 joints and the other limbs are similar to B. insignia. 



The last leg is slender and feebly armed with setae, the internal ramus being tipped 

 terminally with 3 setae, but otherwise unarmed (PI. 17. fig. 16). 



The uropods bear five compound seta?, which are exceedingly long, equalling in length 

 the whole abdomen. 



Length 1-5 mm. 



Colour. Green. 



Male. — Agrees with the male of B. insignis in having a five-segmented abdomen, a 

 more slender body, and no conspicuous projections on the fifth thoracic segment. 



The first antenna, which is geniculated, has 22 joints (PL 17. fig. 15). 



The fifth pair of limbs have the form shown in PL 17. fig. 17. The internal ramus of 

 the right limb is two-jointed and bilobed at the end. 



Occurrence. In the plankton of Lake St. Clair and Lake Sorell. 



BOECKELLA RUBRA, Sp. n. (PL 18. figs. 1-5.) 



Female. — Anterior portion of body narrow and cylindrical; the head and anterior 

 segment fused with it are about equal to the two succeeding segmeuts. 



The fifth segment is large, with very conspicuous lateral projections, consisting of two 

 lobes, the external lobe being very long and spiniform and nearly as long as the first 

 abdominal segment, the internal lobe being smaller and rounded at the end. The first 

 abdominal segment is distinctly sw r oilen in the middle. The abdomen consists of three 

 segments. 



The first antenna consists of 25 joints. 



The last leg has the form shown in PL 18. fig. 3, from which it is seen that the setae 

 on the inner margin of the terminal joint of the external ramus are smaller than in 

 B. insignis, while the inner ramus is well armed with small sete and thus differs from 

 that of B. longiselosa. 



The uropods have five simple setae apiece, about equal in length to the abdomen, thus 

 intermediate in length between those of B. insignis and B. longiselosa. 



Length - 7 mm. 



Colour. Bright red. 



Male. — Similar in form to the female, save that the lateral projections are absent on 

 the fifth segment, and the abdomen consists of 5 segments. 



The first antenna, which is geniculated, has 23 joints, and the penultimate joint has a 

 very marked projection at its end (PL 18. fig. 2). 



The fifth pair of legs have the form shown in PL 18. figs. 4 & 5. They differ from 

 the legs of the other sjiecies in the presence of an extra seta near the internal ramus 

 of the left limb, and in the presence of an extra seta on the claw of the external 

 ramus of the right limb. 



Occurrence. This species occurs in vast swarms in the very old and deep tarns on the 

 Harz Mountains and on Mt. Read. It was never met with in small bodies of water or 

 at lower levels than about 3000 ft. 



