CEPHALOPODA. 475 



cessory fluid subservient to impregnation. Having passed the 

 prostate, the ejaculatory duct communicates with a large muscular 

 sacculus (g), the contents 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 filaments when taken out, 

 even long after the death of the Cephalopod, exhibit, when mois- 

 tened, various contortions, and by some have been regarded as En- 

 tozoa ; but their real nature is entirely unknown, although from 

 the time of Needham,* their first discoverer, to the present day, 

 various speculations and conjectures have been entertained con- 

 cerning them. 



From the pouch of Needham a short canal leads to the penis 

 (A), a short, hollow, muscular tube, through which the fecundating 

 fluid is expelled. It is most probable that the ova of the female 

 are impregnated by the aspersion of the male fluid either during 

 their extrusion, as in frogs, or after they are deposited, as is the 

 case in the generality of fishes ; but this part of the economy of 

 the Cephalopoda is still involved in obscurity. 



(516.) Although we mean to defer any minute account of the deve- 

 lopement of the embryo in ovo until an examination of the eggs 

 of oviparous Vertebrata shall afford more ample materials for eluci- 



dating this important subject, it will be as well in this place briefly 

 to notice the condition of the young Cephalopods previous to their 

 escape from the egg, wherein the first part of their growth is 

 accomplished. Before the egg is hatched, the foetal Cuttle-fish 

 already presents all the organs essential to its support and pre- 



* Needham. An Account of some new Microscopical Discoveries, 8vo. 1745- 



