27 



Ectinosoma: but in all other respects this genus is very different, and apparently 

 more nearly related to the 3 preceding genera. We do not know at present with 

 certainty more than a single species belonging to this genus. 



13. Zosime typica, Boeck. 



(PI. XV). 



Zosime typica, Boeck, Nye Slsegter og Arter af Saltvandscopepoder. Chr. Vid. Selsk. Forhandl. 



1872, p. 46. 



Specific Characters. Female. Body rather short and stout, somewhat 

 depressed, with a very conspicuous constriction in the middle. All segments 

 having the posterior edge distinctly denticulate dorsally, the denticles of the penulti- 

 mate caudal segment being in particular very coarse and partly bifid at the tip. 

 Cephalic segment rather large, considerably exceeding in length the 3 succeeding 

 segments combined, rostral plate short and broad, blunt at the tip, and carrying 

 2 small apical bristles ; the 3 succeeding segments with the epimeral plates some- 

 what exstant laterally. Last segment of metasome abruptly much narrower than 

 the preceding ones, and produced on each side to a slight dentiform corner. 

 Urosome (including the caudal rami) about the length of the anterior division, 

 its 3 anterior segments forming on each side well-marked lamellar expansions 

 each terminating in an acute recurved corner; last segment very small. Caudal 

 rami about 3 times as long as they are broad, slightly constricted at the 

 b;ise, and transversely truncated at the end. outer edge finely denticulate and 

 carrying, at some distance from the tip, a small bristle; the 2 middle apical setae 

 rather coarse and very unequal, the inner one twice as long as the outer, and 

 exhibiting near the base a peculiar angular bend. Anterior antennae with the 

 2nd joint much the largest, and equal in length to the succeeding 4 joints com- 

 bined. Posterior antennae with the outer ramus somewhat shorter than the inner. 

 Last pair of legs with the inner expansion triangular and carrying 3 slender setae, 

 distal joint not distinctly defined from the proximal one, truncated at the tip and 

 provided with 3 apical and one lateral seta. 



Colour whitish gray. 



Length of adult female 0.55 mm. 



Remarks. It seems to me somewhat questionable, whether the form de- 

 scribed under this name by British authors (Brady, Scott) is in reality identical 

 with Boeck's species. Prof. Brady, for instance, indicates the length of the animal 

 to be 0.80 mm., whereas the largest of my Norwegian specimens only measures 



