NATURAL SCIENCES OF PHILADELPHIA. 37 



nicus and A. Golumhianus ?, but a very stout, broad one to the 

 whole head, attached to the outer integument, below the buccal 

 mass, and running along some distance on the floor of the general 

 visceral cavit}", to which finally it becomes attached. 



In describing the genital organs I have used the terras applied 

 to the various organs by Dr. Leid}' in the first volume of my 

 father's work on "The Terrestrial MoUusks of the United States." 

 Each form examined presented differences in these organs. They 

 all agi'ee, however, in having a very large ovary. 



On opening the body of ^. niger (plate XI. fig. c), the genitalia 

 are found in the usual place, the testicle lying quite at the rear of 

 the visceral cavit}' near the extreme point of the upper lobes of 

 the liver, hardly imbedded in it, connected to the ovary by a long 

 epidid3nnis (2). The testicle (1) is globular in form, composed 

 of black, aciniform cfeca. It contrasts in color with the dirty 

 "white of the liver. Color, however, I have not found constant in 

 the internal organs of land shells preserved in spirits. The above 

 described arrangement of the testicle is as usual in Limax^ Arion^ 

 and other slugs. It forms an excellent specific character for A 

 nigei', the position of the testicle being quite difierent in A. Cali- 

 fornicus and ^4. Columbianus?, a.s will be seen below. The epi- 

 didymis (2) is long, convoluted at the end nearer the ovary. The 

 accessory gland is shown in 3. The ovary (11) is large, yellow- 

 ish. The oviduct (8) and prostate (4) show no unusual characters. 

 The genital bladder (9) is large, oval, with a short duct (16). 

 The penis is in a short, stout sac (5), which has a bulb-like swell- 

 ing at its upper extremity, where the vas deferens (7) enters. 

 The latter organ has nothing of peculiar interest. A vaginal 

 prostate, or perhaps dart sac, is shown in 13. The extei'nal ori- 

 fice is described above (p. 34). 



The genital system of A. Californicus is figured in d of plate 

 XI. The testicle does not lie far away, imbedded in, or resting 

 on, the upper lobes of the liver, but lies close against the ovary, 

 in the semicircle formed by the recurving of the apex of the 

 ovary upon itself. In this respect, the position of the testicle is 

 diflTerent from that of most slugs, and affords an excellent specific 

 character. The testicle (1) is kidney-shaped as it is covered by 

 its investing membrane. It appears to consist of closely bound 

 fasciculi of short, white, tubular, not aciniform caeca. The epi- 

 didymis (2) is shprt and still more shortened by its excessive 



