348 ORGANS OF NUDIBRANCHIATA. 



a blunt i^enis, with no ductus ejaculatorius, in combination with 

 a short, broad entrace to the receptacukun seminis. Bcrghia and 

 CoryphcUa have such male organs in combination with long, 

 thin tubes leading to the receptaculum seminis. These con- 

 siderations make it probable that, in copulation, the penis is only 

 inserted into the vagina — not into any of the ducts leading from 

 the latter. 



SUMMAKV. 



Structural modifications of the reproductive organs make 

 it probable that there is a migration of spermatozoa from the 

 receptaculum seminis to the oviduct, along the course of which 

 there may be a chamber specially provided for the fertilization 

 of the ova ; the the prostatic secretion plays an important part 

 in the migration, that the penis, in many species, cannot be in- 

 serted into the receptaculum ; that the eggs, at least in Berghia, 

 pass through the slime gland on their way to the exterior. There 

 are constantly present : An ampulla along the course of the herma- 

 phrodite duct, a rece])taculum seminis, a large prostata, two 

 glands in connection with the vagina, an albumen gland, and a 

 slime gland. The penis may l)e pointed or simply a thickening 

 of the walls of the male opening; there may be a ductus ejacu- 

 latorius or not ; Rizzolia pcrcgrina has an additional gland open- 

 ing at tlic a]:)ex of the penis. There is no bursa copulatrix. 



LITERATURE CITED. 



1. DreVrr. T. F. (1910). ?)lutgefass- und Xerven-svstera 



der Eolidiaden und Tritoniaden. Zeitschrift fur 

 W'issenchaftliche Zoologie. 1910. 



2. Alder and Hancock (1845). A monograph of the British 



Nudil)ranchiate Mollusca. London. 



3. Pelseneer (1893). Recherches zur divers opisthobranches. 



^lem. coiw. et. Mem. sav. etrang. Belgique T. 53. 



4. Trinchese (1877-79). Eolidid?e e famiglie affini del porto 



di Genova. Bologna. 



5. Bergh ([874). Beitrage zur Kenntnis der Aeolidiaden ; K. 



K. Zool- bot. Gesellschaft zu ^^'ien. 



6. Bruel { T904L Ubcr die Geschlechts- und Verdauungs- 



organe von Caliphylla mediterranea ITalle a/S. 



A complete list of literature on the subject will be found in 

 (6)- 



