18 U.S. NATIONAL MUSEUM BULLETIN 2 60 



The tooth of pleonite 4 is more oblique in the other specimens of this 

 species than it is in the holotyj^e. 



Rhachotropis ludificor, new species 



Figure 6 



Diagnosis. — Eyes absent; rostrmn long, broad, somewhat lingui- 

 form, apically obtuse, separated from anterior cephalic keel by deep, 

 slender incision, rostrum slightly down turned; lateral cephalic lobes 

 scarcely falciform, ventral margins straight, each lobe separated from 

 ventral cephalic region by small notch, lobe nearly pointed ; article 1 

 of antenna 1 with two small distal cusps anteriorly and ventrally, 

 accessory flagellum vestigial, represented by small protuberance with 

 three setae; mouthparts like those of E. heUei'^i (Boeck) (in Sars, 

 1895, pi. 150) ; coxa 1 strongly extended forward, blunt apically, coxae 

 2-4 not acuminate ; gnathopods very stout, similar to each other, ar- 

 ticle 5 lobe of gnathopod 2 more slender than that of gnathopod 1, 

 article 2 of gnathopod 1 with medial row of stout spines; second ar- 

 ticles of pereopods 3 and 4 slightly expanded and subovate, article 2 

 of pereopod 5 with long, broad, j^osteroventral lobe, posterior margin 

 evenly and sparsely serrate ; pereonite 7 lacking dorsal tooth, postero- 

 ventral corner extended and subacute; pleonites 1-A each with one 

 posterodorsal tooth, decreasing in size posteriorly, that of pleonite 1 

 long and slender, that of pleonite 4 nearly obsolete, no pleonite with 

 lateral ridges or teeth, pleonite 4 with small, broad, acute process 

 above insertion of uropod 1 ; pleonal epimera 1-3 rounded at postero- 

 ventral corners, epimera 1 and 2 smooth, 3 with large serrations at 

 posteroventral corner; telson cleft about one third of its length. 



HoLOTYPE. — AHF No. 6037, male, 4.5 mm. Unique. 



Ttte-locality.— Station 7221), 27°54'25" N, 115°40'00" W, 1720- 

 1748 m, Dec. 31, 1960. 



Relationship. — This species resembles Rhachotropis distinct a 

 (Holmes, 1908, see Shoemaker, 1930) and R. gracilis Bonnier (1896) 

 but differs from those species by the deeper cleft of the telson, the 

 smaller dorsal teeth of pleonites 2-4 and the absence of serrations on 

 pleonal epimeron 3. Rhachotropis portoricana J. L, Barnard (1964b) 

 has no teeth on pleonite 4 and a short-clefted telson. Rhachotropis 

 faeroensis Stephensen (1944) has a short-clefted telson, a larger dorsal 

 tooth on pleonite 4, a smaller tooth on pleonite 1, and a longer, more 

 evenly tapering rostrum than those of R. liidifxiOT. Rhachotropis 

 anomala K. H. Barnard (1916) differs from the new species in the 

 absence of teeth on pleonites 1 and 3 and the absence of serrations 

 on the third pleonal epimeron. Rhachotropis proxima Chevreux 

 (1911) has a very long, downturned, acutely tapering rostrum and 

 shorter cleft on the telson than does R. ludificor. 



