50 G. 0. SARS. CRUSTACEA. [norw. pol. exp. 



greatest width about in the middle, and almost equalling half the length. It 

 gradually tapers both in front and behind, the anterior extremity being nar- 

 rowly rounded, the posterior deeply emarginated in the middle. The front 

 terminates below in a rather slight rostral projection, carrying 2 very small 

 tentacular filaments. The t-ephalic segment is defined behind from the 1st 

 pedigerous segment by a faint transversal suture. The last segment, on the 

 other hand, is completely coalesced with the penultimate one, and has the lateral 

 parts considerably produced behind, terminating in an acute corner. 



The tail (see also fig. 14) is scarcely Vs as long as the anterior division, 

 and is cyhndric in form. It is, as usual, composed of 4 segments, the 1st, or 

 genital segment, being much the largest, and equalling in length the 2 suc- 

 ceeding ones combined. The last, or anal segment is extremely small. The 

 caudal rami are comparatively short, being scarcely longer than they are broad, 

 and are somewhat divergent. All the setae were broken off in the specimen 

 examined. 



The anterior antennae are rather slender, and somewhat exceed in length 

 the anterior division of the body. They are composed of 24 articulations, 

 the 8th of which is somewhat longer than the next adjacent ones. In the 

 specimen examined, the distal part of both antennae was, however, 

 broken off. 



The posterior antennae (fig. 3) have the outer ramus considerably longer 

 than the inner, and composed of 6 articulations, the 2nd and last of which 

 are the largest, the 3 intermediate articulations being very short. All the 

 joints, except the 1st, carry long ciliated setae. 



The mandibles (fig. 4) have the masticatory part but slightly expanded, 

 with the cutting teeth closely crowded together and rather simple in struc- 

 ture. The palp is scarcely as large as the body of the mandible, and has 

 the outer ramus much smaller than in the 2 preceding forms, and scarcely 

 larger than the inner. The basal part carries 3 setae inside. 



The maxillas (fig. 5) are quite normal in structure, with the masticatory 

 lobe less prominent than in the 2 preceding forms, and armed with about 12 

 partly denticulated spines. The vibratory plate carries 9 plumose setse, the 

 2 proximal ones, however, being rather short. The outer, membranous 

 part of the maxilla, or the palp, exhibits the usual setiferous lappets, the 



