REPORT ON THE AMPHIPODA. 965 



Eusims longipes, Boeck (PI. LXXXVII.). 



I860. Eusirus longipes, Boeck, Forh. ved de Skand. Natuvf. 8de M0de, p. 656. 

 1870. „ ,, Boeck, Crust, amph. bor. et arct., p. 77. 



187G. „ „ Boeck, De Skand. og Arkt. Amph., p. 504. 



Rostrum small, lateral lobes of the head not very prominent; the seventh segment of 

 the perteon carinate, with a small postero-dorsal tooth ; the first three segments of the 

 pleon also carinate, the first two with a postero-dorsal tooth, and the postero-lateral angle 

 produced in a small sharp point ; the third segment with the long lower lobe of the hind 

 margin serrate, the upper serratures pointing downwards, the lower upwards, the postero- 

 lateral corners rounded, the serration continued a very little way along the low T er margin; 

 the fourth segment with a slight transverse dorsal depression ; the sixth segment with 

 the postero-lateral angles tri-denticulate. 



Eyes large, reniform, close to the lateral lobes of the head, with numerous small ocelli, 

 of about equal length and breadth. 



Upper Antenna;. — The first joint much broader and a little longer than the second, 

 each of them distally cut into four sharp points; the third joint narrower than the second 

 and one-fourth its length, distally serrate ; flagellum shorter than the peduncle, of nineteen 

 joints, of which the first is much the longest, equalling the third joint of the peduncle; 

 a calceolus, a cylinder, and some setules form the apical appendages of nearly every joint ; 

 the secondary flagellum of one long slender joint, pectinate on the outer edge, and a second 

 minute joint, the two together nearly as long as the first of the primary. A specimen 

 seemiugly of the same species from Station 150 has thirty-eight joints in the flagellum. 



Loicer Antennas shorter than the upper. First joint a little expanded, gland-cone 

 well developed, decurrent ; third joint short, distally toothed ; the fourth joint as long as 

 the second of the upper antennae, rather longer than the fifth, with setules and spines on both 

 margins, and distally toothed ; the fifth joint much thinner, with many tufts of setules on the 

 upper margin, distally denticulate and armed with spines and setas ; the flagellum much 

 shorter than the peduncle, of seventeen joints, the first the longest, each with an apical 

 group of setules. 



Upper Lip distally broad, with a slit at the centre, a group of long cilia on either side, 

 curving the one group toward the other ; the surface also set with numerous long cilia 

 over the wdiole breadth. 



Mandibles. — The cutting plate on the left mandible elongate, scarcely toothed, with 

 an indication only of a tooth above, and of a division of the large, blunt, tooth-like end 

 below ; the secondary plate divided into eight clear teeth, the general shape of the plate 

 corresponding to that of the principal ; on the right mandible the principal plate has no 

 indication of a tooth above, but below is divided into two strong teeth, the lower of which 

 while in preparation is seen to possess two sharp points ; the secondary plate is of slighter 

 construction than on the other mandible, distally forming two spear-head teeth, with 



