NO. 6.] ACCOUNT OF THE SPECIES. 53 



straight downwards, tip minutely incised in the middle. Lateral parts of last 

 segment produced in female to triangular, posteriorly-pointing lobes. Tail 

 fully half the length of the anterior division of the body, genital segment in 

 female considerably dilated in the middle. Caudal rami slightly widening 

 distally, apical setae not much elongated, and scarcely different in size. 

 Anterior antennae slightly exceeding in length the anterior division of 'the 

 body, 8th articulation larger than the adjacent ones, and in male much 

 elongated, apparently constituting 3 united articulations. Last pair of legs in 

 female with the terminal joint twice as long as the middle one, and very 

 narrow at the base, slightly widening distally, and carrying at the end 4 

 comparatively short denticulated spines, only the outermost of which is 

 distinctly defined at the base; those in male much larger than the natatory 

 legs, right leg the longest, without any inner ramus, outer ramus biarticulate, 

 with the proximal joint bow-shaped, distal joint oblong lamellar, and bent 

 upon the former; left leg with the outer ramus much shorter than the inner, 

 and 3-articulate, last joint very small, setous at the tip, penultimate one 

 produced at the end inside to a rounded denticulated lamella. Length of 

 female about 3 mm., of male 2'50 mm. 



Remarks. This is a very distinct and easily recognizable form, exhibiting 

 in its external appearance, in the comparatively slender form and elongated 

 tail, some resemblance to the Cyclopoida. In the anatomical structure of 

 the several appendages it shows itself, however, to be a true Calanoid. 



Description of the Female. 



The length of the largest specimens amounts to about 3 mm., and this 

 form is accordingly of medium size. 



The general form of the body (see figs. 1 & 2) is rather slender, and 

 the relative length of the 2 chief divisions is somewhat unlike that generally 

 met with in the Calanoida. The anterior division is moderately vaulted 

 above (see fig. 2) and, seen dorsally (fig. 1), is of a very regular oblong oval 

 form, with the greatest width somewhat in front of the middle and consider- 

 ably less than half the length. The anterior extremity, in this view of the 

 animal, appears narrowly rounded, the posterior deeply emarginated in the 

 middle. In a lateral view of the animal (fig. 2) the frontal part appears more 

 evenly rounded, terminating below in a very conspicuous deflexed rostral 



