_68_ 



the original description and figures given by Hesse are very imperfect, it 

 remains still questionable, whether the one or the other of these 2 forms should 

 be regarded as identical with B. ruber Hesse. I should be inclined to believe 

 that these 3 forms in reality represent as many distinct species. They all 

 however agree in the peculiar shape of the transformed last pair of legs, 

 and this is indeed one of the most conspicuous characters distinguishing the 

 present genus from the other 2 genera treated of in the sequal. Scott has 

 described the adult male of the species observed by him. It is about half the 

 size of the female, and differs from it conspicuously, both as regards the general 

 form of the body and the structure of some of the appendages. Thus the 

 anterior antennae are densely clothed, especially at the base, with delicate band- 

 like setae (aesthetasks?), and the legs are built on a quite different type, the 

 4 anterior pairs being apparently well adapted for swimming. A well defined 

 new species referable to the present genus will be described below. 



22. Botryllophilus brevipes, G. O. Sars, n. sp. 



(PI. XXXIII) 



Specific Characters. Female. Body comparatively short and stout, with 

 the anterior division oblong oval in form, and having all the segments con- 

 fluent, no traces of any dividing sutures being observable. Cephalic part 

 defined from the trunk above by a very slight depression, and gradually con- 

 tracted anteriorly, being produced in front to a very small, abruptly deflexed 

 rostral prominence. Dorsal face of trunk gently vaulted and abruply curved 

 behind. Tail considerably exceeding half the length of the anterior division, 

 and perfectly straight; 1st segment much the largest and rather tumid in its 

 proximal part; anal segment somewhat longer than the preceding one. Caudal 

 rami short and somewhat curved outwards, being armed at the extremity with 

 4 strong curved claws. Eye imperfectly developed, though easily observable 

 in the living animal. Anterior antennae short and compressed, very broad at 

 the base, but rapidly tapered distally, being composed of only 4 joints sharply 

 defined from each other, and clothed with a few rigid setae issuing from 

 knob-like prominences of the edge. Posterior antennae a little longer than the 

 anterior and abruptly bent in the middle, 1st joint fully as long as the other 

 2 combined and perfectly smooth; terminal joint linear in form and armed 

 on the outer edge with 2 strong spines, the obtusely rounded extremity of the 

 joint carrying 3 somewhat smaller spines followed by 2 slender setae. Mandibles 

 with the outermost tooth of the cutting edge distinctly bifurcate, palp rather 



