FAUNA OF THE OUTER WESTERN AREA OF THE CHANNEL. 353 



Galathea nexa, Embleton. 



At Positions 58 (six), and 59 (one). 



Depth, 49 fath. 



The tendency in recent years has been to combine this species with 

 the preceding, but I have followed Bonnier (110) in retaining it as 

 distinct. The peculiar /ccc/cs of G. ncxn is remarkable to the naked eye 

 owing to the much stronger spination and hispidation of the first 

 peraeopods especially, and also in the generally shorter form of these 

 appendages than in G. dispcrsa. These distinctions cannot be sexual 

 in character, for though in a different degree they occur in both sexes, 

 and the chelae are more strongly spined in the females of nexa than 

 in the males of dispersa, the difference being especially marked in the 

 large spine on the carpopodite. 



The chief character of distinction used by Bonnier, namely, the 

 relative length of the ischiopodite and meropodite of the third 

 maxillipede, seems to me of little value as compared with the character 

 of the large spine in the ventral region of the meropodite of that 

 appendage. This is centrally situated and isolated in nexa as figured 

 by Bonnier (PL XII, Fig. 7), but more distally situated and as a rule 

 accompanied by a second smaller though prominent spine nearly 

 adjacent and distal to it in dis2}ersa. Bonnier's figure of this joint in 

 dispersa is very misleading, owing conceivably to its having been drawn 

 in such a position as to throw out the perspective, creating the 

 impression that the large spine has a distal position. Milne Edwards 

 and Bouvier (124, p. 72) correct this, describing the position as "vers 

 le milieu du bord infero-interne," which accurately represents the 

 position of the spine in the specimens now under consideration. 

 It is chiefly owing to the same difiiculty of Bonnier's figure chat Hansen 

 (114, p. 31) unites the species with nexa, and records his material 

 under this as the prior name. 



Another character of distinction which may prove of considerable 

 value, is the nature of certain setae closely adjacent to the large spine 

 in question. Bonnier makes no allusion to these setae, but figures 

 them distinctly as faint pencil marks in his drawing of the third 

 maxillipede of G. nexa (PI. XII, Fig. 7). They are from two to four in 

 number, and arise close to the origin of the large spine. In all the 

 specimens of nexa. I have examined, these setae are quite simple, while 

 in those of dispersa. they are clearly pinnate. The only exception 

 occurs in a specimen of disp)crsa in which the largest of them is simple 

 or nearly so, the others being pinnate. This character needs con- 

 firmation in a large number of examples, but the evidence points to its 

 being a reliable mark of distinction. The point is remarkable in view 



