1904] Description of Paracartia Grani. ]_]_ 



attenuated both in front and behind. The last segment of the 

 metasome does not exhibit any trace of the wing-like expansions 

 found in the female, but has the lateral corners simply rounded off. 

 The suture defining this segment from the preceding one dorsally, 

 is conspicuously incurved in the middle. 



The urosome is comparatively much more elongated than in the 

 female, attaining almost half the length of the anterior division. 

 It is narrow cylindrical in form, and is composed of 5 segments, the 

 Ist of which is very small, the 2nd the longest, and the penultimate 

 very short and less perfectly defined from the last one. 



The caudal rami (see fig. 5) are perfectly symmetrical and 

 much smaller than in the female. All the setæ are normally de- 

 veloped and rather elongated, especially the innermost but one. 



The right anterior antenna (fig. 2), which in the species of 

 Acartia is but slightly modified and imperfectly geniculate, in the 

 present form is transformed into a very powerful prehensile organ, 

 somewhat resembling in structure that in the Pontellidæ. It is 

 apparently composed of the same number of articulations as in the 

 female; but the articulations group themselves in several successive 

 sections, which appear very sharply marked off from one an- 

 other. The basal section apparently consists of 8 articulations, 

 some of which, however, are imperfectly defined. It is followed by 

 a very tumid section of about the same length and composed of 4 firmly 

 connected articulations. This section, which more properly answers 

 to the proximal part of the middle section in other Calanoids, is 

 provided anteriorly, like the basal one, with setæ of various lengths, 

 and has moreover on the outer face 2 small knob-like prominences 

 densely fringed with fine spinules, as also near the end anteriorly 

 a dagger-like spine. It contains a very strong muscle extending 

 through its axis, part of it acting upon the following joint, and part 

 being continued throughout the whole length of that joint as a thin 

 chitinous tendon, which joins the terminal section of the antenna. 

 This joint, which in other Calanoids forms part of the middle section, 

 in the present form is so sharply marked off both at the base and 

 at the end, that it has the appearance of a separate section. It 

 is highly chitinized and of considerable length, but rather narrow, 

 especially in its proximal part, and without any setæ, only exhi- 

 biting anteriorly a finely ciliated crest. As stated above, this joint 

 is movably articulated with the preceding section ; but the true hinge 

 of the antenna occurs between it and the following joint which belong 



