BABOR : ON AEIUNCtJLUS AUSTEIACTJS. 



157 



seminis (r.s.) possesses a spherical ampulla, its duct is thin and short, 

 swelling out below till it assumes the shape of an inverted funnel at 

 the point where it joins the dilated portion of the oviduct (d.ov.). 

 The free portion of the oviduct (ov.) is very long, curved some- 

 what in the shape of an S, and furnished with internal folds. Its 

 upper moiety is thin, narrow, and straight, but after the point of 

 attachment of the retractor muscle it becomes stouter and increases 

 perceptibly in size. All three ducts (male, female, and receptacular) 

 enter a large rounded expansion^ of the free oviduct {d.ov.), generally 



Portion of the reproductive organs of Ariuncuhis Austriams, n.sp. 



at. atrium ; c.d. common duct ; d.ov. dilated portion of the oviduct ; ov. free 

 portion of oviduct; r.s. receptaculum seminis; i-et. retractor muscles; 

 sj». sperm duct ; v.d. vas deferens. , " 



but wrongly designated the ' upper atrium.' On laying open this 

 structure the female copulatory lingula may be observed, coiled on 

 itself in three folds, just as it is in Avion Lusitanicus. 



Beyond the attachment of the retractor muscle {ret.) to the oviduct, 

 and close to the point at which it is given off, a muscle passes to the 

 stalk of the receptaculum seminis. It is a fact of some importance 

 that the genital retractor muscle is shown by its remarkable breadth 

 to consist of two separate muscle bands incompletely fused (another 

 instance of paired genital retractors in a species of Arion has been 

 cited by Collinge [6] ), Its point of origin is posterior to the edge of 

 the mantle. The atrium {at.) — generally called the * lower atrium' — 

 is distinctly glandular and folded inwards. There is no pigmentation 

 of the terminal ducts. 



The anatomy of the present species, when compared with that of 

 other representatives of the genus, agrees most nearly with that of the 



This expansion was of enormous extent in the second of the two examples under 

 observation, a condition which is well known to prevail when the animal is 

 in its male phase. 



