REPORT ON THE CUMACEA. 35 



to which it, moreover, seems to bear a closer relation in so far that it is much more 

 movably articulated to the penultimate segment of the trunk than to the first caudal 

 segment. 



The tail is rather slender and somewhat longer than the anterior division of the body. 

 Its segments are regulai'ly cylindrical, with the posterior edge somewhat more emarginated 

 ventrally than dorsally, and forming on each side an obtuse angle. Of the segments 

 the penultimate as usual is the longest. The last segment is rather small and forms 

 posteriorly a rounded prominence arching over the anal orifice. 



The integuments are thin and pellucid, without any distinct sculpturing. 



The colour — to judge from a specimen mounted in Canada balsam — is uniformly light 

 5 r ellowish, without any pigmentary deposits. 



The antennulae (see fig. 1) are seen projecting in front from the sinus between the 

 pseudorostral projection and the anterodateral corners of the carapace. They are of 

 moderate size (see fig. 4) and have the joints of the peduncle successively diminishing a 

 little both in length and thickness. At the end of each joint there are several slender 

 setse, which on the middle joint form a complete whorl around its end. Of the flagella 

 (see fig. 5), the inner one is very small and knobdike, bearing, besides three simple un- 

 equal setae, a single very delicate auditory bristle (fig. 6) with only two diverging cilia 

 at the tip ; a similar bristle is also found affixed to the end of the peduncle internally 

 (see fig. 5). The outer flagellum scarcely exceeds in length the last joint of the peduncle, 

 and is, as usual, composed of three joints, the first being twice as long as the other two 

 taken together. The last joint is very small and bears, besides a few simple bristles, 

 two ribbondike and closely annulated sensory appendages. 



The antenna? of the young male dissected (see fig. 4) are still imperfectly developed, 

 scarcely reaching the length of the anterior division of the body, but yet exhibiting a 

 distinct definition of the peduncle from the flagellum. The peduncle is geniculate at the 

 base, with the proximal part irregularly constricted and bearing three anteriorly curving 

 ciliated bristles, and the distal part cylindrical and exhibiting an imperfect articulation 

 anterior to the middle, but stdl without any trace of bristles. The terminal part of the 

 antenna forms a densely annulated sheath, gradually tapering to the tip, and within this 

 sheath the developing filiform flagellum may be traced. 



The anterior lip (fig. 7) has the form of a small rounded prominence, the posterior part 

 of which is somewhat dilated and slightly emarginated at the free edge, which is finely 

 ciliated. 



The posterior lip (fig. 9) is very delicate and difficult to separate from the adjoining 

 parts, but seems to exhibit the usual structure. The lateral lobes are very thin and 

 membranous, with the inner corner somewhat projecting and incurved, but without any 

 teeth, whereas a delicate ciliation is found along the inner and part of the outer edges of 

 the lobes. 



