174 PROCEEDINGS OF THE NATIONAL MUSEUM YOL. 97 
THE ATLANTIC AND PACIFIC COASTS 
Although there are several similarities between the pycnogonids 
of the Caribbean and Panamic regions, the species found on the 
temperate continental shores of the opposite coasts of North America 
have little in common. The west coast, with its characteristic bold 
cliffs and outlying reefs, accompanied by the upwelling of cold water 
from offshore deeps, has limited the distribution of littoral species, 
with the result that a large number of closely related species have 
been developed. On the east coast the predominant geographical 
features are the long reaches of sandy beaches and outlying shoals, 
washed by the warm, northward-flowing Gulf Stream. These con- 
ditions are correlated with a sparse fauna of widely distributed species 
south of Cape Cod and north of Florida. 
There are some comparable geographical features on the two coasts. 
These are the Bay of Fundy and Puget Sound, both deeply indented 
regions with Boreal-Arctic elements in their faunas, and Cape Hatteras 
and Point Concepcidn, which are the northern limits of many Tropical 
species of marine invertebrates on their respective coasts. 
The similarities between the pycnogonids of the Bay of Fundy and 
Puget Sound are best understood from the following tabulation: 
Bay oF FuNDY Puset SouND 
Nymphon 
grossipes grossipes 
longitarse pixellae* 
stromi 
Phozichilidium 
femoratum femoratum 
Achelia 
spinosa alaskensis 
scabra harrietaet 
longicaudatat 
Pseudopallene 
circularis 678 
Pycnogonum 
littorale stearnst 
*Closely related to N. longitarse, which is reported from Alaskan and Japanese waters. 
~New name for discoidea Exline (Marcus, 1940b, p. 129) 
t Unidentifiable species, possibly A. latifrons or alaskensis. 
**A closely related species, possibly the same, is reported from Alaskan waters, and may also occur in 
Puget Sound (Pseudopallene setosa Hilton, 1942c). 
Along the coast of California there are several localities from which 
at least twice as many species are known as are included in the perma- 
