MOLLUSCGA. 823 
impossible that the spermatophore may be transferred in some cases, 
in the way supposed by Voer, but not always. For the spermatophore 
has been found in the hectocotylus, whilst the filament was yet in- 
closed in its proper sac. In this case the other arms may have 
effected the transfer, as Leuckart conjectures. After it has been 
brought thus far, the propulsive force of the spiral portion of the 
spermatophore must be supposed to come into play in order to begin 
the passage through the tube of communication with the muscular 
pouch of the hectocotylus, whose walls are also muscular. The fila- 
ment at the end of the hectocotylus has been very generally supposed 
to act as a penis. H. Muexier found as many as six of them 
within the capsule of the ovary in Argonauta Clio, that had been 
broken off', and two others in one of the oviducts, so that no fewer 
than eight males would seem to have fecundated this individual. 
It is presumed that when the hectocotylus arm has been cast off, 
it may be successively reproduced. | 
The eggs are laid in heaps, or are connected with each other in 
clusters by pedicles and an adhesive substance. In this respect 
great variety prevails in the different genera. In Loligo, many eggs 
are united in strings of a gelatinous substance; in Sepia they are 
very large and surrounded by a horny dark envelop, which is pro- 
duced into a pedicle at one extremity, and by which the eggs are 
attached to each other, or to foreign bodies. 
In the development of the embryo, when the egg has been laid, 
grooves are formed in that part of the yolk where was previously 
the germinal vesicle, and which do not extend over the whole 
yolk. Here the embryo afterwards appears as a disciform germ, at 
first flat and round, in which, at an early period, different inequali- 
ties indicate the first existence of the mantle, of the eyes, and of the 
funnel, formed at first of two separate halves. This germ-disc be- 
gins to swell gradually in the center, extends itself constantly further 
towards the circumference, and finally surrounds the entire yolk. 
In this way a part of the yolk-sac between the arms at the ventral 
surface is included in the mantle, so that afterwards an internal as 
well as an external yolk-sac is found, the two being connected by a 
narrow pedicle’. 
1 [Op. cit. p. 354.] 
2 Formerly it was supposed that the yolk-sacis connected with the mouth by means 
of this pedicle (CAVOLINI); CUVIER presumed a connexion with the cesophagus; see 
his memoir sur les @ufs de Sciches. Nouv, Ann. du Mus. 1. 1832, pp. 153—160, Pl. 8. 
The chief work that we now possess on the development of these animals and from 
which we have borrowed what has been announced, is A. KOELLIKER Enunckelinga, 
geschichte der Cephalopoden, Zurich, 1843, 4to. 
