and a Variety of Pycnogonum littorale/bom Japan. 283 
certain very material differences. In Zetes the fusiform ros¬ 
trum is connected with the cephalic segment by a joint, so 
that the rostrum may be said to be two-jointed ; in Parazetes 
no joint intervenes; in the latter the rostrum is directly 
united to the long neck-like process of the first segment by 
its own constricted base. In Zetes the maxillipeds (first pair 
of appendages) are four-jointed and chelate, in Parazetes 
two-jointed and not chelate. The palpi in Zetes have ten 
joints, in Parazetes nine. In Zetes the abdomen is two- 
jointed and furnished at the articulation with four long ser¬ 
rated spines; in Parazetes it is one-jointed, clavate, and with¬ 
out appendages. In Zetes the spines of the ovigerous legs 
are slightly serrated, in Parazetes deeply u runcinate 
and Parazetes has the apex of the rostrum four-cheft; Zetes 
has not. 
Pycnogonum littorale (Fabr.), var. tenue , Slater. 
This is a very interesting Japanese variety of the common 
Pycnogonum littorale , which is equally common on the east 
and west sides of the North Atlantic from 40° northwards. 
It is of a much slenderer build than the ordinary P. littorale , 
the rostrum longer in proportion and not nearly so broad, the 
body less flat and shield-like, the leg-bearing lateral pro¬ 
cesses with considerable spaces between them, there being 
little or none in P. littorale ; the oculiferous tubercle more 
prominent, and the eyes larger ; the row of tubercles down the 
median line of the dorsal surface much longer, not so sharply 
pointed, and somewhat scabrous, as is also the abdomen. 
Legs longer and slenderer, the fourth joint equal to the 
first three in length (in P. littorale equal to the second and 
third), and with the prominences less marked; the rest of the 
leg as in P. littorale , except that the spines in var. tenue are 
somewhat longer. 
I subjoin the measurements as compared with a British 
specimen of about the same size. 
P. littorale. Var. tenue. 
millim. millim. 
Length of rostrum . 3 3'5 
Length of body from base of rostrum.... 7 6 
Length of leg. 9 9 
Breadth of body without leg . 4T5 3’5 
Total breadth . 22-15 21-5 
Colour, in spirit, dirty yellow. 
Dredged by Capt. St. John off South-west Japan (33° 15' 
N., 129° 18' E.), July 1876. Presented to the British 
Museum by J. Gwyn Jeffreys, Esq., and numbered in Cata¬ 
logue 78. 11. 
