TRANSACTIONS OP THE SECTIONS. 163 



a stage of the former there is little doubt, as there is more or less resemblance in 

 some of them. They may perhaps originate from the pencil of filaments to be seen 

 in the larger bodies. 



But reproduction in the other Gasteropoda, particularly in the shell-less and water- 

 breathing species, and theair-breatliing (with one or two exceptions), is accomplished 

 by very curious organs. Perhaps they are as complicated in the different species of 

 Helix and Bulimics as in any, and we shall describe them in the former ; hoping 

 that we shall advance a step in the physiology, and make certain the difficult 

 anatomy. Each individual of these animals is considered to be androgynous or 

 hermaphrodite, or to have the organs of both sexes ; yet to become fertile, the con- 

 currence of two individuals is generally required. 



The gland situated at the extremity of the spiral shell was naturally considered 

 by Cuvier to be the ovary ; after examination with the microscope, no one now 

 can doubt it to be ihe testis ; but is it solely such, or does it consist of ovary and 

 testis combined ? This is the present prevalent opinion. But to us it appears a 

 testis, and nothing more. At one time we believed it to be a double organ ; but at 

 last, in the Limax, when we thought the numerous nucleated bodies must be ova 

 par excellence, we found that, on the addition of water and watching them narrowly, 

 they gave origin to spermatozoa, and also showed us the way in which these last are 

 developed, somewhat different from the same thing in the Vertebrata. We see in the 

 testis both large and very small cells, the larger containing several of these last. 

 The small cells occasionally burst within the larger ones, and each gives exit to a 

 spermatozoon, which was spirally coiled in it ; and in the large cell we finally see 

 collected a double bundle of spermatozoa : as often the mother-cell bursts by endos- 

 mosis, and the smaller ones escape, resembling ova or egg-yolks ; but if we add 

 water, and watch, we shall see each one swell, and the contained spermatozoon unrol 

 and make its escape. In Arion each compound cell gives origin to a much greater 

 number of these spermatozoa. They are sometimes seen rolled up into a close coil 

 with the head, or a portion of the anterior part unrolled. With water or a thin 

 fluid, the mature object stops in its movements, and twists upon itself into a battle- 

 door shape. The vas deferens is ciliated and generally stuffed with spermatozoa, 

 often exceedingly vivid in their motion, so that they coil themselves into rapidly 

 rotating cables. This tongue-shaped part is called the glue-organ, and sometimes 

 the testis, by Cuvier ; no doubt it is in part an organ furnishing glue or albumen, 

 but we believe that it also comprehends, together with its granular prolongation, the 

 ovary ; above, it contains diaphanous globules and grains of albumen, but below, these 

 have every appearance of egg-yolks. The ovary of Sepia consists in great part of 

 the same gluey mutter. I think its true structure has never been discovered ; it is 

 best seen in the Limax, late in the year, when less distended ; by teazing and exten- 

 sion, it may be developed so as to be seen to consist of a wide duct and alternately 

 pinnate ramified prolongations from the same. The inferior prolongation is of the 

 same structure. At the base of this ovary ends the vas deferens in a wide con- 

 torted canal, called the matrix by Cuvier, or rather in a groove or false duct running 

 along its side to near its lower extremity ; whence it is continued as a perfect canal, 

 which goes to the intromittent organ. Into the matrix also the ovary opens above. 

 The spermatozoa must pass into what is considered the penis by this canal. It is 

 lined by a mucous membrane, which is easily separated, and the cells of which look 

 at first like ova, but are smaller. I have rarely in the Helix, if ever, found traces of 

 spermatozoa in this duct, but the anatomy seems to prove the nature of the parts. 

 The so-called male organ is situated in the Helix close to the general opening, and 

 of course is everted in coitu. It then carries a remarkable spermatheca, or horny 

 strap or ribbon, with the edges involuted, and the spermatozoa may be found in a 

 tuft at its extremity ; and the penis itself is inserted in coitu into the common duct 

 of the so-called vesicle or "pochc copulative," and its blind appendage. The sper- 

 matheca is formed in the lash-like prolongation of the penis, and along it may be 

 seen moving spermatozoa. The blind appendage seems to be distended sometimes 

 with a thin fluid, perhaps acting by endosmosis on the spermatozoa, and the vesicle 

 is a reservoir from which the spermatozoa, or at least the vivifying fluid containing 

 them, is discharged into the matrix, where it meets the egg-germs, easily obtaining 

 ingress from above and the side. In manv species of Mollusks I have found the 



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