38

Scientific Memoirs by

      Among the Sponges collected by the " Investigator" we commonly find that
the anchoring-ropes of the Hyalonematidœ are—as has been abundantly noticed
and commented upon elsewhere—encrusted with zoophytes of the genus Palythoa
and with Cirripede crustaceans of several species. The connexion here, however,
is probably accidental, because we do sometimes find both dead and living shells
and dead corals invested with both Palythoa and Scalpellum.

      But when, in the depths of the Andaman Sea, we meet with the feeble little
macrurous crustacean Richardina spongicola entangled in the Hexactinellid
sponge Hyalonema masoni, and not elsewhere, we are inclined to suspect that the
relation between the two animals is in some way a necessary one. The nearest
relatives of Richardina also live imprisoned in Hexactinellid sponges: these are
Spongicola venusta, which is habitually found in Euplectella, and Spongicola
Koehleri, which is found in Regadrella phœnix. The species of Stenopusculus
also—a genus allied to Spongicola —commonly live with sea-anemones.

      Another very good instance of commensalism, in which a sponge plays a
part, has often been observed on reefs of the Andamans, where the little
weak inoffensive crab Cryptodromia pileifera is never found unprotected by a
sponge—each crab being completely concealed beneath a little tightly-fitting
sponge shaped like a cap. But, of course, sheltering under sponges and Ascidians
is a well-known family-habit with the Dromiidœ.

      References to the commensals of Hexactinellid sponges will be found in the following
papers:—

           J. E. Gray, in Ann. Mag. Nat. Hist. (3) XVIII. 1866, p. 489, and XIX, 1867
p. 44.

           Semper, in Wiegmann's Archiv für Naturges. XXXIII, 1867, i. p. 84; and
Ann. Mag. Nat. Hist. (4) II. 1868, p. 26.

           T. J. Moore, in Ann. Mag. Nat. Hist. (4) III. 1869, p. 198.

           Willemoes Suhm, in Zeitschrift für wiss. Zool. XXVI, 1876, Appendix, p. lxxiv.

           Miers, in Journ. Linn. Soc. Zool., XIII. 1878, p. 507.

           Also in the " Challenger" Reports, by F. E. Schulze, on the Hexactinellid Sponges;
and in Filhol, La Vie au Fond des Mers, Paris, 1885.

           On the general subject of commensals of Sponges see:—

           H. J. Carter, Parasites of the Spongida, in Ann. Mag. Nat. Hist. (5) II. 1878,
p. 157.

           Weltner's summaries in Wiegmann's Archiv für Naturges. for 1887, 1888, 1890,
1892, 1894.

           The following are some of the papers on Sponges and Crustacea as commensals:—

           Hesse, Ann. Sci. Nat. Zool. (4) XV 1861, page 105: Henderson, Challenger Narra-
tive, Vol.,1, pt. 2, p. 899: Scott, Proc. Nat. Hist. Soc. Glasgow, 1886, p. 146: Senoner
Zool. Garten, XXVII, 1886, p. 92: Bidder on Celesia, Zoologischer Jahresbericht, 1893,
Porifera p. 10 (Colesia, Atti. Soc. Ligustic. Sci. Nat. Genova, IV, 1893, p. 217).