160 Transactions. — Zoology, 



On each side of the oesophagus there is a large sahvary gland (fig. 5 c), 

 the ducts opening into the posterior portion of the buccal mass. Below the 

 buccal mass and oesophagus lies a peculiar tongue-shaped organ (fig. 4 d), 

 which is ductless, and fastened in its anterior half to the body wall, but free 

 posteriorly. It is composed of rounded nucleated cells, and is grooved 

 along its upper surface. It may represent the organ of Semper in other slugs. 



The stomach is long, and makes nearly three right-hand spiral turns. 

 It passes gradually into the intestine, which turns forward, and follows the 

 stomach back through its windings to the oesophagus ; it then turns sud- 

 denly back, round the posterior branch of the aorta (fig. 5/), and again 

 descends nearly to the end of the stomach ; it then turns suddenly forward, 

 and once more following the convolutions of the stomach, ends in a short 

 straight rectum, which opens on the right side below and in front of the 

 respiratory opening. The liver (fig. 5 e) is formed of two compact spindle- 

 shaped lobes. In J. marmorea the intestine turns forward immediately after 

 receiving the hepatic ducts, but in J. bitentaculata it descends nearly to the 

 posterior end of the liver, making another half turn before it turns forward. 



Rejyroductive system (fig. 7). The ovotestis is subrotund in form and 

 divided longitudinally below by a groove running from the hermaphrodite 

 duct, which is purplish. It is of a dead white or pale yellow colour. It is 

 remarkable for its position in the animal, lying in front of the rectum, while 

 in all other slugs with which I am acquainted it is placed posteriorly, among 

 the folds of the liver. The albumen gland is long and tongue-shaped; and 

 of a pale yellow. In J. marmorea there are two other large accessory glands 

 at its base, but these are absent in J. bitentaculata. It is, however, quite 

 possible that these so-called accessory glands may be folds of the oviduct 

 which I was unable to unravel. The vas deferens separates from the oviduct 

 at its commencement in J. marmorea, and at about the middle in J. hiten- 

 taculata. If the supposed accessory glands in J. marmorea are but folds of 

 the oviduct, then the vas deferens would separate in the same position in 

 both species. The penis is long, narrow, and tapering, and the vas deferens 

 enters it at its posterior extremity. The retractor of the penis (fig. 7 k) 

 arises from the musculature of the foot, on the left side, in a line with the 

 respiratory opening ; it is inserted into the posterior extremity of the penis. 

 The spermatheca (fig. 7 g) is purplish brown, globular, with a short neck ; 

 it is situated on the oviduct, a short distance from the genital opening. The 

 penis lies across the animal's neck, over the nerve collar. The spermatozoa 

 are gradually thickened at one end, which is spirally twisted. In J. mar- 

 vwrea the ovo-testis lies on the upper surface, and is exposed when the 

 animal is opened from the back ; in J. bitentaculata it is hidden, but can be 

 seen from below. 



