SEXUAL ORGANS. 121 



at the point where it unites with the albuminiparous gland, exists 

 a small cfecum, sometimes simple, as in Bulimus, sometimes 

 lobulated {Helix palliata^ H. thyroides, Succinea ovata), and 

 the walls of which are sometimes glandular ; it is believed that 

 the ovules are fecundated at the moment of passing into its cavity. 



The accessory organs to the vagina consist of narrow, elon- 

 gated, ramified diverticles, united in two groups and opening on 

 each side bj' a common canal. Thej' have been called multifid 

 vesicles, mucous glands, vaginal prostates. The number of 

 branches of each vesicle is 61 {Helix vermiculata), 30 to 40 {H. 

 pomatia), 25 {H, aperta), 12 {H. ce}<pitum), 8 {JE. aspera), 4 

 {H. conspu7-cata) ^ 2 {H. serpentina). In H. pisana and H. 

 arhustorum there is only found a simple vesicle on each side ; 

 finally, in Helix lenticula and H. acuta, the vesicle is unique 

 (Moquiu-Tandou). In a number of species having no mucous 

 vesicles we find a glandular lining of the vagina or vaginal pros- 

 tate (Zonites, Daudebardia). Alongside the mucous vesicles 

 opens into the vagina the sac of the curious dart (xviii, 9, 10), 

 which consists of one or two ovoid purses having muscular walls, 

 and within which are secreted a calcareous object, like a sharpened 

 point or lance-head, with trenchant edges, rounded base, and 

 channeled sides. This teliim veneris is expelled at the moment 

 of copulation and buries itself in the teguments of the snails in 

 coitu. 



The canal of the copulatory pouch usually has a diverticle 

 called the copulatory branch ; its size is narrow and uniform, 

 and its length sometimes considerable {Helix Niciensis). 



The vestibule is in relation with some appendages, the use of 

 which is not known ; such are the horn-like appendages of Parma- 

 cella. The genital cloaca is encircled by mucous glands in 

 Limax marginatus : Moquin-Tandon designates them under the 

 name of vestibular prostates. 



The deferent canal may be encircled with prostatic glands, as 

 well as its free portion. 



The cul-de-sac of the penis-pouch is usually provided with* a 

 very long cylindrical appendage or Jiagellum, in which is formed 

 the spermatophore. Nevertheless, a spermatophore equally exists 

 in species having no flagellum ; in which case, the secretion 

 of this envelope of the seminal fluid takes place in the deferent 

 canal (Dubreuil). The prostates or mucous glands open in the 

 copulatory sac in Orthalicus and Liguus. 



In order to understand the disposition of the genital organs 

 in the androgyna having separate orifices, or ditremata, we will 

 take for type those of Limnasa. The hermaphroditic gland and 

 its excretory canal have the same disposition as in the monotre- 

 mata. The albuminiparous gland is placed at the posterior 



