Til 



MOLLUSGA— GENITAL ORGANS 



235 



This apparatus, in Limncea, consists of a large evaginable terminal widening, into 

 which the vas deferens projects in the form of a papilla. Blood pressure causes the 

 penis sheath or prseputium to be evaginated through the genital aperture, into which 



s ^ ■ 



Fig. 191. 





14 



Fig. 192. 



Fig. 191.— Genital organs of Limnsea stagnalis (after Baudelot). 1, Male genital aperture ; 

 2, larger penis tube (penis sheath) ; 3, protractors ; 4, smaller penis tube ; 5, vas deferens ; 6, pro- 

 stata ; 7, flattened widening of the vas deferens ; S, hennaplirodite duet ; 9, hermaphrodite gland ; 

 10, part of the digestive gland (liver) ; 11, albuminous gland ; 12, nidamental gland ; 13, uterus ; 

 14, pear-shaped body ; 15, receptaculum seminis ; IG, vagina ; 17, female genital aperture. 



Fig. 192. — Genital organs of Oncidiiim celticum (combined from the figures of Joyeux- 

 Laffuie), somewhat diagrammatic ; only part of the vas deferens is drawn. 1, Male genital aperture ; 

 2, penis sheath (prteputium) ; 3, penis papilla ; 4, vas deferens ; 5, uterus, the seminal furrow in 

 the uterus is indicated by dotted lines ; 6, cagcum of the uterus ; 7, oviduct and vagina ; 8, csecal 

 appendage ; 9, receptaculum seminis ; 10, female genital aperture ; 11, albuminous glands ; 12, csecum 

 of the hermaphrodite duct, 13 ; 14, hermaphrodite gland. 



it is again withdrawn by means of a retractor. In other species of Oncidium, the 

 copulatory apparatus is complicated by the occurrence of accessory penis glands and 

 variously -shaped cartilaginous armature. ; 



