Fauna Associated with Crinoids of Tropical Coral Reef, etc. 83 
other than the spines on the dactyli of the thoracic legs, but the animals 
are thigmotropic and swim back immediately to the host when they 
have been detached. 
Galathea elegans Adam and White. (Plate 1, Fig. 5.) 
G. elegans, ADAM AND WuiteE, Voyage of the Samarang. 
G. longirostris, DANA. 
G. deflexipous, HASWELL, Proc. Linn. Soc. New South Wales, vol. v1; Miers, Zool. Coll. H. M. 8. 
Alert. 
G. longirostris, SourHWELL, Anomura, Ceylon Pearl Oyster Rep. Roy. Soc., part V, p. 220, 1906. 
In earlier literature there are only three records of the occurrence of 
galatheids on crinoids. The first is that of Dana, who originally 
described G. longirostris from a crinoid dredged at Fiji; the second is 
that of Haswell, who founded a new species G. deflexipous, associated 
with Synalpheus comatularum on an unidentified crinoid. The third 
likewise concerns G. longirostris, which is mentioned by Southwell as 
obtained near Ceylon, clinging to Antedon bella. 
G. elegans Adam and White, G. longirostris Dana, and G. deflexipous 
are all very closely related. They all possess a long rostrum with from 
5 to 10 small lateral denticles, a very typical dorsal ornamentation, and 
have a similar colour scheme, with longitudinal stripes of pigment on 
the dorsum. The first-named species has not been noted as occurring 
on crinoids, but this may be the fault of the collectors. Balss, in 
describing a specimen from Japan, which he assigns with some doubt to 
G. elegans, says with regard to its occurrence: ‘‘Wahescheinlich an 
Comatuliden, wie es Haswell von der nahe verwandten G. deflexipous 
und Southwell von G. longirostris Dana angeben. Darauf weist die 
bunte Farbung hin, die wohl als eine mimetische zu deutenist.’’ Prob- 
ably the whole group of related species are crinoid dwellers. If not, it 
will be strange that so marked a pattern should occur on a free-living 
galatheid, when that is a character so definitely associated with crinoid 
commensalism, both here and in other groups. 
The three species are principally defined with regard to the characters 
of the rostrum; thus: 
G. elegans: G. longirostris: G. deflexipous: 
Rostrum more than half thelength ofthe Rostrum fully as _ Differs from elegans only in 
rest of the carapace, “‘ with 7 small den- long as half the the fact that the rostrum 
ticulations on each side’’ (Haswell). carapace ‘‘mi- is entirely deflexed. 
But Balss gives the latter number as 9. nutely 5-6 serru- 
But most important of all, the original late.” 
figure only shows 5 or 6. 
With regard to the third species Miers says: 
“Tn more than one of the specimens in the Museum collection the rostrum 
is slightly deflexed, and I think that G. deflexipous Haswell, from Albany 
Passage, should be regarded merely as a marked variety of G. elegans.”’ 
In my own specimens the number of denticulations on each side is 
from 6 to 7; in one individual there were 6 on one side, 7 on the other. 
