NO. 5.] ACCOUNT OF THE SPECIES. 115 



filaments may be discerned. Posterior antennae with the terminal joint long 

 and narrow, with 6 comparatively short, anteriorly-curving apical setae, and 

 another much longer seta issuing from a distinct ledge inside the tip. Pos- 

 terior maxillipeds with the hand perfectly smooth, dactylus long and slender, 

 finely denticulated inside. Natatory legs with the spines of the outer ramus 

 very slender, the apical one almost attaining the length of the whole ramus, 

 all bordered with a hyaline, smooth rim. Last pair of legs rather small, with 

 the 2 apical spines of the same structure as those on the natatory legs, the 

 larger one reaching only a little beyond the middle of the genital segment. 

 Length of adult female 2"45 mm. 



Remarks. This form does not agree fully with either of the 2 hitherto 

 known species, though approaching somewhat nearer to L. aculeata than to 

 L. sguillimana. It differs materially, from the former, however, in the per- 

 fectly smooth caudal segments, as also in the relative length of these seg- 

 ments. Moreover, on a closer comparison, some minor differences may be 

 found to exist in the structural details. 



Description of the Female. 



The length of the body in fully adult specimens amounts to 2'45 mm., 

 and this form accordingly grows to a somewhat larger size than either of 

 the 2 hitherto known species, the larger of which (L. aculeata), according 

 to Dr. Giesbrecht, has a length of 2'30 mm. 



The body is highly pellucid, allowing the intestine, the anterior part of 

 which forms a large oval dilatation (see figs. 1 & 2), to be distinctly seen 

 through its thin walls. The general form is very slender and elongated, with 

 the 2 chief divisions rather sharply marked off from each other. The anterior 

 division is somewhat tumid, and, seen dorsally (fig. 1), exhibits a rather 

 regular oblong oval or obovate form, with the greatest width not quite 

 attaining half the length, and occurring in front of the middle. The anterior 

 extremity appears evenly rounded, the posterior more attenuated. As in 

 Onccea, this division consists of 6 well-defined segments, the 1st of which, 

 the cephalic segment, is about the length of the 4 succeeding ones combined. 

 The penultimate segment is slightly emarginated in the middle, and has the 

 lateral corners far less prominent than in L. aculeata, and rounded off at 

 the tips. The last segment of the trunk, as in other Gyclopoida, is very 



