1909.] FROM THE BAY OF BISCAY. 867 



These groups occur on each joint from the 1st to the 9th, then on 

 alternate joints to the 27th, The accessory jiagellum (fig. 35) : 

 l-jointed, narrowly laminar, with a large cleft spine and two 

 divergent setje at the apex. 



Male (fig. 36). — Only the 1st joint of the jiedimcle remaining. 

 This has the dentiform projections and sensory ciliated hairs as 

 in the female, but is furnished posteriorly with 8 ti-ansverse rows 

 or tufts of fine sensory bristles, extending partway round the 

 inner side. 



Inferior antenna. Female (fig. 34). — The 2nd and 3rd joints 

 of the peduncle apically dentate ; the 4th long and broad, ^\•ith 

 sinuous upper margin, thickly setose on its anterior surface, and 

 produced at the posterior angle to a setiferous lobe ; the 5th, 

 subequal to it in length, is much narrower, with numerous small 

 setse anteriorly and several long fine ones distally. The Jiagellum 

 consists of about 20 joints, each furnished anteriorly with a 

 cluster of small setfe, those on alternate joints being longer than 

 the others. I found no trace of the calceoli mentioned by 

 Bonnier. 



Male (fig. 36). — Only four joints of the peduncle remaining. 

 The upper margin of the 3rd joint has four tufts of the sensory 

 bristles in the right antenna, five in the left ; the 4th joint 

 carries twelve of these in the right and thirteen in the left 

 antenna, the apical group being the largest, and containing also 

 several long sensory ciliated hairs. This joint is produced at the 

 posterior angle, as in the female, to a lobe bordered with long 

 fine setse ; on the posterior margin are several clusters of the 

 ciliated hairs, with a longitudinal i-ow of 7 or 8 of the small ones 

 proximally, each set in a little depression similar to those on the 

 1st joint of the superior antenna. 



Upper and lower lips. Female (figs. 38, 39). — The figures given 

 by Bonnier are not of the same magnification. Inner lobes of the 

 lower lip covered with fine hairs. 



Mandibles. Female (figs. 41, 42, 43, 44). — Cutting -plates greatly 

 curved, Avith a strong obtuse tooth above, bidentate below in the 

 right mandible, rounded and recurved in the left. These plates 

 appear subject to great variation. Bonnier gives {loc. cii. p. 651) 

 " apex allonge, robuste, sans denticulations ; le processus acces- 

 soire est elargi et presente cinq a six dentelures sur I'un des 

 appendices, tandis que sur I'autre il est rudimentaire, et tridente ; 

 il est accompagne d'une ran gee de cinq petits poils courts." In 

 the three specimens examined I found the accessory plate of 

 the left mandible with 8 teeth in two specimens (fig. 44), 9 in 

 the other, 5 or 6 spines in the spine row, the accessory plate 

 following the deep curve of the cutting-plate. In the rio-ht 

 mandible the accessory plate is of a more complicated structure, 

 divided below, the inner portion tuberculate with 3 or 4 strong 

 teeth ; the other portion variable as regards the number of teeth 

 but with one above and one below strongly produced (figs. 41, 42). 

 In one specimen the accessory plate was bi'oken, leaving only the 



Proc, Zool. Soc— 1909, Xo. LIX. 59 



