1374 THE VOYAGE OF H.M.S. CHALLENGER. 



Phronimopsis tenetta, n. sp. (PL CLXTV.). 



Head deeper than long, deeper than the perseon ; first two segments of the peraeon 

 partially coalesced, deeper than the two following, and those two deeper than the three 

 that succeed thern ; the first three segments of the pleon much longer and deeper than 

 the perseon-segments, the posterolateral angles rounded, though there is a minute point 

 showing where the convex lower margin and convex part of the hinder margin meet. 

 The skin apparently without pigment-flakes. 



Eyes probably having an upper and lower group of ocelli, but in our specimen they 

 were scarcely visible except near the lower margins of the head. 



Upper Antennae. — Peduncle short, tumid, the first joint a little longer than broad, 

 the two following much shorter than their breadth ; the first joint of the flagellum about 

 as long as the peduncle, narrowing to the distal end, its broad breast lined with a brush 

 of long filaments, the breast not quite reaching the apex of the joint ; the second joint 

 rather longer than broad, the third joint narrower but considerably longer than the 

 second. The remainder missing. The second joint of the flagellum, besides having 

 apical filaments, has a narrow decurrent process, the blunt apex of which is tipped with 

 long filaments. 



Lower Antennae. — Gland-cone broad, projecting from the wall of the head ; the third 

 (first free) joint cylindrical, as broad as long ; the fourth joint scarcely so large as the 

 third, widened distally ; the fifth joint not quite so long as the third and fourth together, 

 distally a little narrowed and produced over the slightly bulbous base of the first joint of 

 the flagellum, this joint being slender, longer than the fifth joint of the peduncle ; the 

 remainder missing. 



Upper Lip. — I believe it is correct to say that this is unsymmetrically bflobed. 



Mandibles. — Cutting plate divided into six or seven teeth forming a convex edge ; 

 the right mandible (fig. m.) without a secondary plate, the left mandible having a 

 secondary plate similar to the primary, about equally long ; the teeth were not counted 

 as this plate was seen only in profile ; the lower edge of the trunk and the upper part 

 of its surface to the rear of the cutting plate are strongly ciliated ; to the rear of the 

 ciliated portion is a broad molar tubercle, the crown of which has a shar]?, slightly 

 crenate edge ; the three -jointed palp is much longer than the trunk, slender, the first 

 joint the thickest, equal in length to the slightly curved third, the second longer than 

 either. 



Lower Lip. — The forward margins finely ciliated. The mandibular processes with 

 rounded apices. 



First Maxillae. — Inner plate not strongly developed ; outer plate having much of 

 its surface crowded with hair-like setules or spinules, from among which distally a series 

 or group of about seven strong spines emerge ; one of the seven appears to be apically 



