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132 MOLLUSCA.
Mollusks in confinement.
Advice as to keeping and rearing terrestrial mollusca in confinement is
given by H. Seibert, Nachr. mal. Ges. ii. pp. 72-74.
Collecting and Preserving.
The methods of making and preserving microscopical preparations
of the radula and jaw of Gastropods are discussed by
W. Kobelt, Nachr. mal. Ges. ii. pp. 58-62.
A method of collecting small land-shells, especially those
which live in damp places, by taking moss &c. from the irrigation
channels of the meadows, and examining them at home fresh
and dried, is given by H. Seibert, /. c. p. 96.
Classification.
The importance of the dentition for the classification of the
Mollusca is discussed by Kobelt, Ber. Senck. Ges. 1869-70,
pp. 65-71 ; he comes to the conclusion that neither this nor any
other character is absolute.
CEPHALOPODA.
A general account of the Cephalopoda, recent and fossil, is
given by H. Woodward, chiefly from posthumous papers of his
brother. Stud. iv. 1870, pp. 1-11, 241-249, with 4 good plates.
A. LAFONT has made several observations concerning the
development of the spermatozoids and the copulation of various
species of Cephalopods at Arcachon. The substance of the
spermatophores is produced by the glands, which have been
called seminal vesicles by Cuvier, and for which the author
proposes that of " vesieules d'Edwards;" the spermatozoids
themselves come from bodies which resemble in all respects
true ovula, and are developed within the testicle. How spermatozoids
come into the spermatophores could not be ascertained.
The copulation has been observed in Sepia filliouxii,
Lafont. A male and female interlace their arms, and are situated
mouth against mouth; clusters of spermatozoids and the
torn remains of the spermatophores are expelled from the funnel
of the male, and find their way by the current of the water into
the branchial aperture of the female. The arms have, at least
in this genus, no direct function in the copulation. Ann. Sc.
Nat. (5) xi. 1869, pp. 109-LW.
MEIGEN'S experiments and reasoning concerning the hydrostatic
quality of the shell of Nautilus result in conclusions similar
to those advanced by the late Prof. Kei'erstcin, viz. that the air
within the air-chambers of the shell serves only to give to the
whole animal a specific weight nearly equal to that of the water,
and that the descending or ascending is effected only by the