MALE GENEEATIVE SYSTEM. 601 



subservient to impregnation. Having passed the prostate, the ejacu- 

 latory duet communicates with a large muscular sacculus (#), the con- 

 tents of which are very extraordinary. This sacculus is, in fact, filled 

 with innumerable white filaments, each about half an inch in length, 

 arranged parallel to each other, and disposed with much regularity. 

 There are three or four rows of them, one above another, entirely 

 filling the sac; and they are maintained in situ by a delicate spiral 

 membrane, but are quite unconnected with the sac itself. The fila- 

 ments when taken out, even long after the death of the Cephalopod, 

 exhibit, when moistened, various contortions, and by some have been 

 regarded as Etitozoa. 



(1606.) These remarkable spermatic filaments (the famous "filament 

 machines " of JSTeedham) present, in fact, a very complicated structure. 

 Their form varies in different species ; but in their essential composition 

 they are all found to consist of a long tubular sheath (fig. 297, 2, 3), 

 composed of two membranes, and enclosing a long tube, convoluted upon 

 itself like an intestine, which is filled with an opake white fluid, in which 

 are contained millions of zoosperms ; and the apparatus to which it is 

 attached anteriorly constitutes an ejaculatory instrument, by the aid of 

 which the spermatic secretion is forcibly ejected. These " spermato- 

 phores" as they have been named by Milne-Edwards, serve as vehicles 

 for the conveyance of the seminal fluid into the generative system of 

 the other sex, notwithstanding the absence of any copulatory apparatus. 



(1607.) A most extraordinary modification of the male sexual organs 

 is met with in the males of the Argonaut, Tremoctopus, and probably of 

 other kindred genera, in which one of the arms is so strangely modified, 

 both in its shape and structure, that Cuvier mistook it for a parasite, de- 

 scribing it, under the name of ffectocotyles, as " a long, parenchymatous 

 worm, compressed at the an- 

 terior extremity, where the Fi g- 299 - 

 mouth is situated, having 

 its inferior surface furnished 

 with suckers, from sixty to a 

 hundred in number, arranged 

 in pairs, and furnished with 



a SaCCuluS, Situated at the i, 2. Male Argonaut, of the natural size, repre- 



n/iafarW f^rtrPTYiitv of its sented in front and in profile, showing the sacculus 



posterior extrei in wMch the Hecfcocotylus is contained; from a 



body, which is filled With the specimen preserved in spirit. 3. Sacculus, in which 



,,,, -jo.)? the Hectocotylus may be distinguished through 



folds Ot the OVldllCt. its fcran8parent walla . The specimen from which 



(1608.) The HectOCOtyluS this figure was taken having been preserved in 



, , . spirit, is, of course, contracted in all its dimen- 



Argonautce*, as this strange sions> 

 appendage is still called, is, in 



fact, a portion of the Argonaut itself, developed in a remarkable sac, which 

 supplies the place of the left arm of the third pair. The male Argonaut 

 * Henri Miiller, Ann. des Sc. Nat, 1851. 



