1909.] FROM THE BAY OF BISCAY. 861 



Second maxilla (fig. 30). — Both plates covered with fine hairs ; 

 inner plate slightly the smaller, with a row of 4 plumose hairs on 

 the inner surface, the proximal one the longest. The apices of 

 both plates are provided with long stiff setse, serrated for half their 

 length. 



MaxilUjyeds (fig. 28). — Female. Inner plate, apical margin 

 straight with 2 small, broad teeth, and 5 setiform feathered spines ; 

 the inner margin carries 2 stout feathered spines. Outer plate 

 reaching to the middle of the 2nd joint of the palp ; a short, 

 curved, flat spine with serrate edges is inset at the apex, with 3 

 setiform feathered spines on the right maxilliped and 4 on the left ; 

 the inner margin is produced beyond the row of spines into a 

 delicate crenulated border (similar to that of the second gnathopod 

 palmar border of the male). Male exactly as in female, except for 

 an increased number of spines and setfe ; 3 along the inner margin 

 of the inner plate ; and 5 setiform spines on the apical margin of 

 both outer plates in addition to the curved spines. The immature 

 specimen 3 mm. long has 3 on each outer plate and the curved 

 spine at the inner angle is more slender ; the construction and pro- 

 portions are the same as in the adult. Palp, 2nd joint very large, 

 much larger than the 3rd ; 3rd produced a little anteriorly over 

 the finger : 4th joint or finger longer than the 3rd, with a distinct 

 nail, anterior margin edged with rows of minute spinules. 



Gnathopods very iinequal in size in the full-grown animal, 

 though in the young there is not much difference between them. 

 In the ' Huxley ' specimens, the small 3 mm. one has the hand of 

 the second gnathopod only one-fourth longer than the hand of 

 the first ; in the intermediate specimens 5-5*5 mm. the difference 

 increases, the second being twice the length of the first ; and 

 the inequality is still greater in the largest specimen 7*5 mm. Of 

 the two males examined the smaller one, 7 mm., has the second 

 gnathopod hand twice the length of the first ; the difference is 

 greatei" in the larger specimen of 11 mm. 



First gnathopod (figs. 9 & 10). — Female. 2nd joint large, curved, 

 carrying proximally, on either side, several extremely long and 

 delicate setse ; 4th joint cup-shaped ; 5th large, produced to a 

 transparent lobe at the posterior distal angle on the outer side, 

 the anterior margin shorter than that of the 6th joint in all the 

 specimens, more markedly so in the young. The shape of the 6th 

 joint or hand varies with age ; in the small 3 mm. specimen, the 

 posterior margin is convex, palm defined by a sensory spine ; but 

 in the larger specimens the palmar angle is well produced, the 

 hind margin is straight and about the same length as the palm. 

 Chevreux, however, describes it thus, " son bord palmaire se 

 confond avec le bord posterieur, et forme avec lui une courbe 

 reguli^re." In examining the 'Huxley' specimens I found that 

 the hand in the natural position is held turned inwards at an 

 angle to the rest of the limb, bringing the palmar angle under- 

 neath, thus masking the real shape of the joint, and giving it the 

 convex appearance described by Chevreux. In the figure (fig. 10) 



