712 CLASS XII. 
are parts which correspond to the lateral venous sinuses of the 
decapod crustaceans (see above, p. 605), and to the two lateral 
venous hearts in the Cephalopoda dibranchiata*. Consequently the 
two arterial stems of the gills convey venous blood, which, having 
become arterial in the gills, is brought back to the heart by four 
branchial veins (two on each side). The walls of these venous 
sinuses may at the same time be regarded as secreting organs, 
which correspond to the appendages of the veins in the Cephalopoda. 
Each of these sinuses, moreover, is situated in a cavity or a space 
with thin walls, to which the water has free access by a fissure 
which opens close to the external opening of the genital organs. 
Besides the circulation of the blood in vessels and in spaces 
without proper walls, as already described, another system still of 
canals or interspaces has been discovered, that is filled with 
water in conchifers, as in many other invertebrate animals’. It is 
probable that in the description of the circulating system of the 
blood, a confusion with these canals has occasionally occurred *. 
It was generally supposed formerly, that all the conchifers 
were of one sex, not so much bisexual, as indeed all female, there 
being no other organs of propagation except ovaries’. But if 
such were really the case, these animals ought not to be styled 
female, but sexless. An organ for the preparation of germs could 
not, when the germ required no impregnation, be an ovary; the 
germ which, without the influence of sperma is developed into a 
new animal, ought rather to be named a detached bud than an 
1 Tn a letter to my deceased friend Nirzscu of Halle, MeckeEt’s Archiv f. Anat. u. 
Physiol. 1828, s. 502, and in the first edition of this Handbook, 11. bl. 35. What 
Y. SIEBOLD advances as my opinion, and with which he professes to agree, that the 
parts described by Bosanus correspond to the appendages of the veins in Cephalopods, 
is not mine, but indeed a later guess of Boyanus himself (/sis 1820), who in fact had 
too much love of truth to conceal that his opinion respecting the respiration of 
conchifers was something of a paradox (eine in ironischer Anwandlung, etwas keck und 
paradox ausgesprochene Meinung). 
2 DELLE CHIAJE Memorie sulla storia e notomia degli animali senza vertebre, I. 
p- 259, and foll. pp. 269, 270; V. Barr in Frortep’s Notizen, 1826. 
3 Compare on this point V. SirBoLp Lehrb. der vergl. Anat. I. s. 279—281. [See 
Lerypre Ueb. Cyclas cornea LAM., MUELLER’S Archiv, 1855, pp. 54—57, from whose 
observations it would seem that the opinion of DELLE CHIAJE, that the fine pores and 
canals of the water-system communicate with that of the blood, is perfectly correct. | 
4 Even in the work of DEsHayEs, T’raité de Conchyliol., begun a few years back, 
this statement is found p. 284. 
