34 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 125 
or North America. It was known previously from the coastal regions 
of India, the Red Sea and Suez Canal, South Africa, South America, 
and Australia. Now it appears to be a circumglobal, essentially warm 
water species, but with spotty distribution. Several large gaps remain, 
however, notably the eastern Pacific and eastern Atlantic. The dis- 
junct distribution of S. walkeri might be explained on the basis that 
the present populations are relicts of a once continuously distributed, 
circumtropical cosmopolite; however, the alternative explanation that 
follows seems more plausible. 
As previously mentioned, shipping probably has been responsible 
both for the wide dispersal and for the discontinuous distribution of 
Sphaeroma walkeri. The fact that this wood-boring species has been 
taken from wooden hulls and that it has a spotty pattern of distribu- 
tion support this view. It is likely that transport by driftwood or by 
natural rafts carried by currents has been involved to some extent 
in the distribution of this species, but it seems unlikely that the vast 
distances and other barriers between some of its recorded localities 
could have been traversed by such passive carriers. 
Another wood-boring isopod in the buoy collection, Sphaeroma 
terebrans, also has been found on ship bottoms as well as in dead 
wood. These agencies doubtless have been responsible for the world- 
wide distribution of this species. A documented case of dispersal of 
an isopod by ships is given by Chilton (1911). He recovered live 
females and males of a sphaeromatid (Cymodoce tuberculata) from the 
hull planking of the British Antarctic research vessel Terra Nova in 
dry dock in Lyttelton, New Zealand, after her arrival from Port 
Phillip, Australia. Since the species was unknown from New Zealand 
but common in Australia, Chilton concluded that these isopods were 
transported some 1200 miles between the two ports. 
Floating seaweed carried by currents probably has contributed to 
the wide distribution of two idoteids that are well represented on New 
England buoys, namely Jdotea balthica and J. metallica. Both species 
have marked swimming ability and the habit of clinging to floating 
seaweed. 
The new locality records for Carpias bermudensis provide a basis for 
the following hypothesis regarding the origin and dispersal of this 
species: Hitherto known only from Bermuda, it was found on several 
buoys on the east coast and Key West regions of Florida. It is now 
suspected that this species originated and is well established in the 
Antillean region and that it has been transported northward to Ber- 
muda by the Gulf Stream, possibly clinging to floating seaweed. The 
well-known affinity of the Caribbean and Bermudan marine faunas 
support this interpretation. The converse possibility—origin in 
