46

Scientific Memoirs by

      Richard, Sur les Parasites et les Commencaux des crustacés, in Arch. de Parasitol
II. No. 4, pp. 548—595.

      Peters, in Wiegmann's Archiv, f. Naturges. XVIII, 1852, i. p. 283 (Crustacea in
Mollusks).

      Semper, in Zeits. Wiss. Zool. XI, 1862, p. 105 (Crustacea and Mollusks).

      F. Müller, in Weigmanns Archiv f. Naturges. XXVIII, 1862, i. p. 194 (Crustacean
and star-fish).

      Graffe, in Verh. Zool. bot. Ges. Wien, XVI, 1866, pp. 586, 588 (Crabs and Corals
Crabs and Mollusks).

      Verrill, in Ann. Mag. Nat. Hist. (3) XX, 1867, p. 230 (Crab embedded in Sea-urchin).

      Streets, Bull U. S. Nat. Mus. VII. 1877, p. 110 (Crab in cloaca of Holothurian. The
same genus of crabs—Lissocarcinus-Asecla —is found in Indian waters, but its exact
habitat has not been noted).

      Lucas, Ann Soc. Entom. France (5) X, 1880, Bull. p. cxvi. (Crabs in Oysters).
Joliet, in Arch. de Zool. Experim. X, 1882, p. 118 (Pontonia in an Ascidian).

      Haacke, Zool. Garten, XXVI, 1885, p. 37 (Dromia and Ascidian).

      Woodward, Proc. Zool. Soc. 1886, p. 177 (Crab and Pearl oyster).

      Kingsley, American Naturalist, Vol. XXII, p. 894 (in " Something about Crabs")

      Henderson, Contribution to Indian Carcinology, in Trans. Linn. Soc., Zool., (2) V.1893.

      Coupin, Compt. Rend. CXIX, 1894, p. 542 (Crustaceans with Bivalves).

      Coutière, Ann. Sci. Nat. Zool (8) IX, 1899 (Alpheidæ).

5. Commensalism among Mollusca.

      Some instances of the well known association of Crustacea with Bivalve
Mollusks have already been mentioned, namely Pontonia with Tridacna as has
been noted by numerous observers—and Pinnoteres in various Bivalves, as
has been known since the days of Aristotle.

      The following cases may also, possibly, be illustrations of commensalism:—

      The gastropod mollusk Pleurotoma symbiotes has been dredged in deep
water, in three different places, off Ceylon. The animal in every case was alive,
and its shell copiously encrusted by one and the same species of Palythoa. The
obvious advantages that would accrue, both to the mollusk and to the sea-anem-
one, from this association, and the apparent constancy of the association,
must not, however, lead us to forget that other species of Palythoa are sometimes
found attached to dead shells etc., and are commonly adherent to the anchor-
ropes of Hexactinellid sponges.

      The living Shells of Turbo indicus, which is another gastropod inhabitant
of the depths of these seas, frequently give attachment to a sponge, and also
to a Cirripede crustacean of the genus Scalpellum.

      The small species of Gastropod Mollusca that one constantly finds deeply
anchored in the sea-urchin Astropyga radiata are more probably parasites than
commensals.