ATLANTIC AND CARIBBEAN PYCNOGONIDA—HEDGPETH 181 
The taxonomy of the Boreal-Arctic and Tropical species of Nymphon 
is in such a chaotic state that it is with some hesitation that I propose 
two new species for the genus. Ninety or a hundred species have 
been assigned to this unwieldy genus, yet there seems to be no end to 
the variations of trivial characters on which the species are based. 
Although Nymphon attains it maximum development of species and 
numbers of individuals in the Arctic and Antarctic regions, species 
are by no means rare in tropical regions, and, as Giltay (1937, p. 
87) remarked, more will probably be found by future collectors. 
Ten species of Nymphon have been identified from the regions 
considered in this report, and three more occur within the northern 
limits of the area. As they are usually Arctic species, they have 
been included in the key in brackets in order to keep the key as 
simple as possible. The species south of Newfoundland fall into two 
groups: A, spinosissimum, hirtipes, and tenellum, which have a heavily 
setose trunk and legs and rather short tarsal joints in proportion to 
the propodus; and B, grossipes, longitarse, strémi, rubrum, macrum, 
giltayi, and floridanum, which are characterized by the lack of closely 
set setae on the trunk and legs, and, except for floridanum, by rela- 
tively long tarsal joints. 
The collection of Nymphon sluiterti Hoek from the Gulf of St. 
Lawrence in 1932 indicates that this species may be a rare member 
of the New England—Newfoundland fauna, although this is the 
extreme southern record for this species. Another Arctic species, 
common on the coast of Greenland and in Fox Basin, Nymphon 
brevitarse Krgyer, occurs as far south as the Strait of Belle Isle but 
so far is unknown from the southern part of Newfoundland. A third 
Arctic species, Nymphon elegans Hansen, was taken by the Godthaab 
at station 14, latitude 55° N., longitude 56°34’ W. (off Labrador), 
and may be expected at moderate depths off Newfoundland. 
KEY TO WESTERN ATLANTIC NYMPHONS SOUTH OF NEWFOUNDLAND 
1. Tarsus half as long or less than half as long as propodus___-__--_--------- 2 
Tarsus almost as long as or longer than the propodus_-_-_-__------------ 5 
2. Lateral processes separated by their own width or less; legs and trunk setose_ 3 
Lateral processes separated by more than their own width; legs and body not 
THICKIVASELOSSh eee ee oe eee oe floridanum, new species (p. 196) 
3. Lateral processes separated by less than half their own width; neck about as 
LOB PIAS MWIGE Sit = 4202) 57 Pakage ite ee eRe AOS ie. reo Ite eS 4 
Lateral processes separated by more than half their own width; neck slightly 
ROME ORG NAT VAG Cae) eects er oe ee 2 ea tenellum (p. 185) 
4. Auxiliary claws at least half as long as terminal claw__spinosissimum (p. 183) 
Auxiliary claws about one-fourth as long as terminal claw__hirtipes (p. 183) 
5. Fingers of chelae comparatively thick, shorter than palm, a few large spines on 
soleroispropoduss.22 22. ste aha el ee pay Tie Pry eS 6 
Fingers of chelae slender, usually long or longer than palm; without large 
BPIMESZONESOlEs Of Apr O 1 OL US x ea pan he ne SR be ar 7 
