42 A. MANUAL OF AMERICAN LAND SHELLS. 



the Northeast to its beiug peculiarly adapted to colonization. I have 

 elsewhere related my successful attempt to colonize the allied Tachea 

 nemoralis.* 



III.— OF THE GENERATIVE APPARATUS. 



All the terrestrial Gasteropoda under consideration are monoecious 

 or hermaphroditic, though none are capable of self-impregnation. They 

 are also mostly oviparous. 



Their genital system is complicated, and liable to such variation in its 

 details as to furnish excellent generic and specific characters. I have 

 therefore, when possible, given descriptions of the system in the de- 

 scriptive portion of my work, under each species. I will here give only 

 a general description of the development of the system : The testicle is 

 a single globular mass of aciniform coeca in some genera; in others it 

 is composed of numerous fasciculi of long cceca; itis free, or imbedded 

 in the upper lobe of the liver ; its position, as well as the shape of its 

 coeca, being different in the respective genera. 



The epididymis is an undulated, or moderately tortuous tube, leading 

 from the testicle to the inner side of the junction of the ovary with the 

 prostate gland. It opens into a groove on the inner side of the interior 

 of the oviduct, which is continuous, at its inferior extremity, with the 

 vas deferens. Opening into the termination of the epididymis, and 

 lying against the inner side of the ovary, is a small, compound, follicu- 

 lar body, which appears to be common to all the terrestrial Gasteropoda, 

 and is known as the accessory gland of the epididymis. The prostate 

 gland is a white or cream-colored body, occupying the inner side of the 

 whole length of the oviduct. It has a transverse, striated appearance, 

 and numerous openings into the groove leading from the epididymis to 

 the vas deferens. 



The vas deferens is a comparatively short tube, passing from the pros- 

 tate gland to the penis sac. The position of its junction forms a spe- 

 cific character ; sometimes it joins the summit of the latter, at others 

 it enters near the base. 



The penis sac is generally a long, cylindroid, irregular body, lying at 

 the right anterior jiart of the visceral cavity, and joining at its termi- 

 nation a short cloaca. Its form is, however, very variable, and is an 

 excellent specific character, as is also the point of insertion of the 

 retractor muscle, which has its origin from the muscular investment of 



■* See Tachea hortctisis. 



