60 THE VOYAGE OF H.M.S. CHALLENGEE. 



short transverse keel at the antero-lateral angle. The posterior edge of the telson is 

 folded into six acute spines, and from the tip of each a broad convex carina runs forwards 

 on the dorsal surface of the telson. The marginal carina reaches to the anterior border, the 

 intermediate stops a httle short of this border, and the third or submedian runs forwards 

 for about half the length of the telson, where it abuts upon the median prominence. 



The marginal spines of the telson have acute tips and swollen bases with convexly 

 rounded outlines, and the deep sulci between them are bordered by convex ridges. The 

 outer spine is simple ; the intermediate has its outer edge simple and a secondary spine 

 on its inner edge near its base ; the submedian spine has a secondary spine on its outer 

 edge near its base, and twelve or thirteen acute dentations on its inner edge. The dorsal 

 surface of the basal joint of the uropod ends posteriorly in two acute spines, and there is 

 a rounded lobe outside the base of the outer one ; its ventral surface ends posteriorly in 

 a process divided into two acute curved spines, the outer longer and with a rounded 

 tooth near its base on its inner edge. 



The paddle of the exopodite is more than half (^) as long as the second joint, which 

 has a rounded process on the inner edge of its base, about twelve movable spines on its 

 outer edge, and a ventral terminal immovable spine. 



The eyes are cylindrical, with rounded cornege (fig. 6), and the first and second 

 antennae are about equal in length. The eyes hide all the shaft of the first antenna 

 except the terminal joint. The tip of the simple dactyle of the raptorial claw is curved 

 outwards, and its inner edge is barbed with minute serrations. 



The endopodite of the first abdominal appendage of the male (PL XV. fig. 8) is 

 very similar to that of Gonodactylus chimgra. The terminal joint is divided by a 

 deep marginal notch into a small outer lobe and a large inner lobe, both of which 

 are rounded and not separated by a suture. The fixed limb e of the petasma is swollen 

 at the base and it ends in a single acute hook. 



Remarks. — Notwithstanding the fact that this is a widely distributed species, no 

 minute description of it has been published, as Miers' description ' gives little except the 

 points of difference from Gonodactylus chiragra, and the only figure, the telson shown in 

 Miers' fig. 9, is misleading, as will be seen by comparison with our fig. 4, PI. XIV. 

 In his figures, as well as in his descriptions, he represents the central area of the dorsal 

 surface of the telson as made up of three pairs of curved carinse on the sides of the 

 median one, whereas more careful examination will show that the third or outermost 

 pair do not belong to the central elevated convex system so characteristic of this and 

 related species, but to a distinct eminence on the anterior edge of the telson. 



This Species is very closely related to Gonodactylus chiragra. The species next 

 described, Gonodactylus glabrous, is in many respects intermediate between the two, 

 the three forming a sharply defined natural group or subgenus. It may readily be 



1 Ann. and Mag. Nat. Hist., ser. 4, vol. siv. p. 341, and ser. 5, vol. v. p. 120. 



