ATLANTIC AND CARIBBEAN PYCNOGONIDA—HEDGPETH 175 
nent fauna of Woods Hole. At Dillon Beach (about 40 miles north 
of San Francisco), for example, 9 species have been collected. About 
21 species have been described from the central California coast, 14 
of which have been collected in the vicinity of Pacific Grove.” Of 
particular interest is the large number of species of Achelia and 
Tanystylum on the California coast. 
The occurrence of so many endemic species on the California coast, 
together with the physical conditions (upwelling of cold water and 
bold headlands) that limit their distribution, brings to mind the 
suggestion of Marcus (1940a, p. 197) that the limited locomotive 
powers of the Pycnogonida as a group have influenced the develop- 
ment of a large number of closely related species. The wider dis- 
tribution of many species in the Atlantic, apparently associated with 
the Gulf Stream and floating sargassum, is not duplicated elsewhere 
and supports rather than disproves this hypothesis. 
A few characteristic North Pacific species are found along the west 
coast as far south as the vicinity of San Pedro: Pycnogonum stearnsi, 
Phorichilidium femoratum, and Lecythorhynchus marginatus. The 
Boreal Nymphon grossipes has not been collected south of Puget 
Sound. 
In brief, the pycnogonids of the east coast south of Woods Hole 
are southern species that have worked their way northward, whereas 
the California coastal fauna is a mixture of endemic species, northern 
forms, and such southern species as Anoplodaciylus erectus, Tany- 
stylum intermedium (both found as far north as Pacific Grove), 
Nymphopsis spinosissima, and Pycnogonum rickettst (northernmost 
records, Dillon Beach). 
Although at least three species of pycnogonids have been taken in 
tow nets in the Japanese region (Ohshima, 1933), few northwestern 
Pacific species are found on the American coast. The anomalous and 
puzzling distribution of Ammothella bi-unguiculata (Naples, southern 
California, Hawaii, and Japan) is the most conspicuous example. 
The distribution of the genus Lecythorhynchus (Ammotheidae) may 
be of more zoogeographical significance. One species, L. hilgendorfi, 
is known from the western Pacific, and another, marginatus, is a 
character species of the California coast. Hilton (1942d) has de- 
scribed a third species of this genus, L. ovatus, from Hawaiian waters. 
SYSTEMATIC DISCUSSION 
The literature on the Pycnogonida is fantastically large and is 
scattered in dozens of bulletins, journals, and proceedings, many of 
them unavailable even in the largest libraries. Type material has 
fared no better; as Calman (1923, p. 267) sourly remarks, specimens 
10 For further information concerning California species see Hedgpeth (1941) and Hilton’s numerous 
preliminary papers, listed in the bibliography. 
