3OO Introduction to Animal Morphology. 



arrangements of the ducts are liable to vary,* and to 

 them may be appended receptacula seminisf and 

 nervous glands, with clear and opaque cells.J The 

 penis is protrusible like a glove-finger, sometimes spi- 

 rally rolled when not in use. In Pulmonates there is 

 always a multilobar hermaphrodite gland, often with 

 csecal processes (Limnsea), with an often tortuous her- 

 maphrodite duct ending in a double tract, the female 

 product escaping by an oviduct into a dilated uterus, 

 below which is a pouch-like receptaculum scuii/iis and 

 an albumen gland ; the female organ ends in a va- 

 gina. The male duct begins as a ciliated groove, 



* The vai A. Genital gland branched, diffused in 



the body. 



I. Male and female glands separate, with a branched prostate, and 

 both ducts f.ir forward = Klysia (Placobranchiata) [Pagenstecher 



i.aving a hermaphrodite gland]. 



II. M.ilr and female glands not separate, but distinguishable ; pros- 



i:,'ina far back = Pontolimax (Abranchiata). 

 and female glands not separate, but distinguishable; pros- 

 tate unknown, all sex ducts united = Tergipes (Gymnobranchiata). 



III. Male and female glands united; prostate simple; follicles sepa- 

 rate = Rhodope (Abranchiata). 



Male and female glands united, prostate simple; follicles her- 

 maphrodite = Phyllirhoe (Abranchiata). 

 B. Genital gland consolidated behind the liver ; prostate simple. 



IV. Male and female ducts at first united, then separate, ovarial, 

 vaginal and seminal openings close in a cloaca = Fiona, Facelina, 

 Tethys, Doris, Dendronotus, Pleurobranchus, Pleurobranchaea. 



V. Male and female ducts united for along extent, with no inner 

 canal to the penis ; genital openings separate, but close together 

 = Pleurophyllidia, Umbrella. 



Male and female ducts united for a long extent, with no inner 

 canal to the penis ; penis far in front of the vagina, with a ciliated 

 canal = Aplysia, Doridium, Gasteropteron, Philine. 

 t Described as the Swammerdamian vesicle. 

 ^ Umbrella has a ccecal pouch between the vagina and uterus. 



