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 1 . 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 2 . It is 

 probable that in the description of the circulating system of the 

 blood, a confusion with these canals has occasionally occurred 3 . 



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 4 . 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 In a letter to my deceased friend NITZSCH of Halle, MECKEL'S Archivf. Anat. u. 

 Physiol. 1828, s. 502, and in the first edition of this Handbook, n. bl. 35. What 

 V. SIEBOLD advances as my opinion, and with which he professes to agree, that the 

 parts described by BOJANUS correspond to the appendages of the veins in Cepkalopods, 

 is not mine, but indeed a later guess of BOJANUS himself (Isis 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 ausgcsprochene Meinung}. 



2 DELLE CHIAJE Memorie sulla storia c notomia degli animali senza vertebre, n. 

 p. 259; an( l fN' PP- 2 ^Q, 270 ; V. BAER in FRORIEP'S Notizen, 1826. 



3 Compare on this point V. SIEBOLD Lehrb. der vergl. Anat. I. s. 279 281. [See 

 LEYDIG 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, Traite de Conchyliol., begun a few years back, 

 this statement is found p. 284. 



