270 LAWSON^ ON HELIX ASPERSA AND HORTENSIS. 



formed the part of testes ; ^ more recently it has been con- 

 ceived by Henrich Meckel, Siebold, Gegenbaur, and Moquin- 

 Tandon^ that the so-called ovary of the older writers is in 

 reality an hermaphrodite gland, each lobule of which has 

 contained within it a second, the external secreting ova, the 

 internal zoospores, the oviduct also having a second vessel 

 invaginated by it. Of these four, however, the two latter, 

 who have been the latest to write upon the subject, deny 

 that any included sac or duct exists. Moquin-Tandon, 

 moreover, follows Van Beneden in his ideas concerning the 

 prostate. 



The following are some of the reasons which urged the 

 adoption of the view I have now put forward. 



CONCERNING THE OVARY. 



(a) Arguing merely from authorities, I feel inclined to 

 agree with Cuvier and his disciples, inasmuch as his oppo- 

 nents, though men of great research and vast fame, are 

 but few in number, and are equally divided in a matter of 

 observation, upon which, in fact, their argument is wholly 

 based. 



(b) I have carefully, from time to time, examined single 

 lobules under the microscope with the aid of the compressor, 

 and never have I succeeded in bringing any contained sacculi 

 into view; although, when I placed several lobules in the 

 compressor, I had an appearance produced somewhat resem- 

 bling invagination, but evidently the result of some lobule 

 becoming superimposed, and then pressed into the substance 

 of another. 



(c) There being no invaginated duct leading from the ovary, 

 the zoosperms, if there secreted, would have a greater tendency 

 to pass into the normally widened uterus than into the con- 

 stricted vas deferens (indeed, the latter passage could not be 

 effected, as there is no communication of the vas deferens 

 with the uterus), and so would pass away externally, and 

 be lost ; but such a state of things could not reasonably 

 exist. 



(d) From my own observations I may make use of Mr. 

 Handcock^s most ingenious argument applied to the Nudi- 

 branchs, that, as the zoosperms were found in a condition of 

 imperfect development in the sperm- sac, and fully matui'ed 



* This was Cuvier's idea, and also that of J. F. Meckel, Carus, Erdl, 

 Sister, Beudach, Pappenheim, Berthelen, Pyfe, and Rymer Jones. Van 

 Beneden also held it ; but he considered that gland a prostate, which is here 

 maintained, to be in the sperm-secreting organ. 



