178 STALK-EYED CRUSTACEA. 
The second pair of legs are a little longer than the first pair, with a 
longer and slenderer chela. The second segment (basipodite) is armed with 
a small spine at the distal end of the inferior edge. The inferior edge of the 
merus is armed with thirteen spines. The carpus is armed with one long 
spine at the distal end of its lower margin. The chela is unarmed, except- 
ing the pectinate grasping edges of the fingers. 
The third pair of legs reaches forward a little beyond the proximal end 
of the chela of the preceding pair. The coxa and basis are robust, the suc- 
ceeding segments tapering to a thread-like tenuity in the propodite and dac- 
tylus. All of the segments are naked and unarmed. The merus contributes 
one half to the length of the whole appendage, being more than twice as 
long as the propodite. The dactylus is shorter than the carpus. 
The fourth pair of legs are very short, reaching only to the proximal end 
of the merus of the second pair of legs. The inferior margin of the dactylus, 
propodite, and distal end of the carpus is beset with coarse bristles. 
The fifth pair of legs, when extended, attain to the middle of the merus 
of the second pair. The dactylus is flattened, broad, rounded at the distal 
end, and furnished with long marginal sete. 
Length, 145 mm. ; carapace, including the anterior dorsal tooth, 55 mm. 
Station 3384. 458 fathoms. 1 specimen. 
This species is second only to P. princeps Smith, in size. It is most 
nearly related to P. tarda Kriéyer,* from the North Atlantic. It differs from 
the latter in having the dorsal line of the carapace more convex, the pos- 
terior part of the carapace higher in proportion to the anterior part, the 
dorsal keel of the carapace rounded except on the anterior gastric region, 
and the anterior rostrum-like tooth longer and differently shaped. The 
proportional length of the segments of the third pair of legs appears to be 
quite different in the two species: in P. tarda, according to Kroyer, the pro- 
podite and dactylus are of equal length and four times as long as the carpus, 
while in P. magna the dactylus is even shorter than the carpus, which is 
itself only one sixth as long as the propodite. In P. tarda, according to 
Kroyer, the lower margin of the second segment of the second pair of 
legs is furnished with three spines; in P. magna this margin is unarmed 
but for the tooth at its distal end. 
* Naturhist. Tidsskr. 2 R., I. 453, 1845; Voyages de la “Recherche” en Scandinavie, etc., Crustacés, 
Plate VI. Fig. 1. ; 
