1438 THE VOYAGE OF H.M.S. CHALLENGER. 



wards ; to the central piece of the apex there is attached a stump of the second joint, 

 which completes the limb in this sex. 



Pleopods. — Peduncles stout, squared or oblong, with the lower margin lobed on 

 either side, and sending out a small hammer-headed process over the outer ramus ; the 

 two coupling spines are small, but elaborately spined, the heads being smooth domes with 

 zigzag edges, and a set of three retroverted teeth projecting from each margin of the 

 shaft ; the single cleft spine is not very elongate, with a rather broad, strongly ciliated 

 stem, the arms rather short and thin, the longer roughened on two margins, the shorter 

 having the subapical dilatation ; the outer ramus has eleven, the inner ten joints ; the 

 first joint in each ramus being broad, but not very long, the rami themselves broad, not 

 tapering rapidly. 



Uropods all extremely transparent, except in the upper part, where they show 

 hexagonal cell markings, visible also in other parts of the animal ; the ends of all are 

 rounded, sometimes more flatly in the first and third pairs than in the second, and all 

 have a marginal ciliation of extreme fineness, most easily observed at the distal ends, 

 and perhaps absent from the upper parts ; there do not appear to be any peduncles l 

 distinct from the supporting segments ; all the pairs have a shape in general oval, but 

 with a constriction on the inner side near the base ; the first pair reach as far as the 

 third, and are therefore longer than the third, but a little less broad ; the second pair 

 attached at the top of the double-segment, are less broad than the first and shorter than 

 the third ; the third pair attached at the lower end of the double-segment, bend inwards, 

 so that one plate lies upon the other for most of its length. 



Telson rather broader than long, about half the length of the third uropods, in shape 

 an inverted arch, with the apex broadly rounded. 



Length. — The specimen, in the position figured, measured a quarter of an inch, in a 

 straight line from the front of the head to the end of the third segment of the pleon. 



Locality. — April 4, 1875; North Pacific, south of Japan; lat. 25° 33' N., long. 

 137° 57' E.; surface ; surface temperature, 69°. 



Remarks. — In the young taken out of the mother, and less than a twentieth of an 

 inch long, the general shape and proportions of the adult are already seen, the fourth 

 joint is distally widened in the first four pairs of peraeopods, but the fifth joint is com- 

 paratively broader ; the pleopods have as usual in the young two-jointed rami, the second 

 joint much shorter than the first. 



The name " Anchylom.era Blossevillii" Milne-Edwards, afterwards written " Anchy- 

 lomera Blossevillen," will probably cover all the species named in the synonymy, since 



1 Milne-Edwards, Hist. Nat. des Crust., t. iii. p. 87, says that these uropods " sont riSduites en un petit article 

 basilaire a peine perceptible, auquel est attached une grande lame ovalaire de consistance membraneuse." Bovallius 

 regards the membranous plates as themselves the peduncles. Whether they are in fact the peduncles without rami, or 

 the rami without peduncles, or the rami and peduncles combined, cannot at present be decided, but there is perhaps as 

 much to be said for the third view as for either the first or the second. 



