132 
MOLLUSCA. 
Mollusks in confinement. 
Advice as to keeping and rearing terrestrial mollusca in confinement is 
given by II. Seibert, Nacbr. mal. Ges. ii. pp. 72-74. 
Collecting and Preserving. 
The metliods of making and preserving microscopical pre- 
parations of the radula and jaw of Gastropods are discussed by 
W. Kobelt, Nacbr . 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 irriga- 
tion channels of the meadows, and examining them at home fresh 
and dried, is given by II. Seibert, 1. 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. I-I4, 241-249, with 4 good plates. 
A. Lafont has made several observations conceriiiiig 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 ^Wesicules d^Edwards;^^ the spermatozoids 
themselves come from bodies which resemble in all respects 
true ovula, and are developed within the testicle. How sper- 
matozoids come into the spermatophores could not be ascer- 
tained. The copulation has been observed in Sepia filliouxiiy 
Lafont. A male and female interlace their arms, and are situ- 
ated 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. I09-I33. 
Meigen^s experiments and reasoning concerning the hydro- 
static quality of the shell of Nautilus result in conclusions similar 
to those advanced by the late Prof. Keferstein, viz. that the air 
within the air-chambers of the shell serves only to give to the 
whole animal a specific weight nearly ecjual to that of the water, 
and that the descending or ascending is effected only by the 
