184 TWELFTH ANNUAL REPORT. 



mens. Brady figures a similar reduction in the number of Joints 

 of the antennae as that seen in our specimens. The fifth foot too, 

 is less well armed with spines, but otherwise the agreement is tol- 

 erably close- 



Genus Harpacticus, Milne-Edwards. 



Elongate or expanded laterally; head united with the first thor- 

 acic segment; first and second abdominal segments coalescent; 

 antennae S-, 9-jointed; mandibuiar-palp 2-branched, large; second 

 pair of maxillipeds strongly developed; outer ramus of the first 

 pair of feet 2- or S-jointed, inner ramus 2-jointed; first and second 

 joints of outer ramus elongated, second joint of inner ramus short; 

 both rami of following pairs of feet 3-jointed; ova-sac single. 



Harpacticus chelifer, Mueller, (var. n. ?) 



The species inhabiting the galf of Mexico resembles H. gracilis^ 

 Claus, in the length of the setge and some other peculiarities; but 

 the antennary palp is more like H. chelifer^ with which it closely 

 agrees in most respects. Remembering that the entomostraca 

 have their highest development in temperate and arctic regions, the 

 small size and greater proportional length of setae and stylets may 

 be explained, H. gracilis from the Mediterranean takes the place 

 of the true H. chelifer of the North sea, and is regarded by Brady 

 as the same species. Our form would, in this case, stand more 

 nearly related to the typical form. Both branches of the first feet 

 are two-jointed and the antennary palp has three spines on its dis- 

 tal segment. 



Genus Bradta, Boeck. " (1872.) 



Antennge very short, 6-, 7-join ted; antennules of moderate size 

 longer than antennae, with a 2- or 3-jointed palp; mandibular palp 

 large; maxillipeds rather large, outer branch (first foot-jaw of 

 Brady?) much as in Calanidce; first four pa\rs of feet nearly alike; 

 fifth pair small, not lamellate. 



This peculiar genus is not yet well circumscribed and defined, 

 and it is much to be regretted that lack of time prevented from 

 ascertaining how far the western species agrees with the generic 

 characters of the European form and thus determining the validity 

 of the assumed generic criteria. That our species is a member of 

 the genus can not be doubted, but the hurried examination which 

 could be devoted to it failed to cover the entire structure. 



