REPRODUCTIVE ORGANS OF KUKENTHALIA BOREALIS. 191 



A brood-pouch was developed only in few zooids. It could not 

 be decided whether all the zooids of the colony were mature, the 

 material being little fit for dissection. From the above-mentioned 

 facts one might, however, conclude that the members of the 

 colony do not attain sexual maturity at the same time, probably 

 owing to different age. 



As appears from text-figures 2 and 3 the part of the genital 

 pouch which contains the genital glands is of a bulb-shaped 

 form. On one side a large swelling, enclosing the distal part of 

 the oviduct, is visible, and its form varies, owing to the degree 

 of development of the brood-pouch, as will be described in the 

 following. 



Male. — The testis is composed of numerous spermatic vesicles 

 and a long vas deferens. 



As has been mentioned above, the testis is placed on the out- 

 side of the body-wall, invested by an outgrowth of the mantle, 

 projecting into the common test. The vas deferens, which is a 

 duct of considerable length, extends into the peribranchial 

 cavity and opens into it. 



Text-figure 4. 



-vd 



Kukenthalia borealis (Gottsch.). 



Vas deferens. X 33. 



A. Vas deferens, usual form. B. Vas deferens, coiled up. 



vd. Vas deferens. 



The spermatic vesicles are pyriform glands which are arranged 

 in two bundles, on account of which the testis appears to be 

 bipartite. The male glands open into two sperm-ducts, each 

 bundle having its duct, and "these unite as a rule into a main 

 sperm-duct, the vas deferens (cf. text-figs. <LA & 5). 



In one individual examined another arrangement was observed. 

 Here the two ducts did not join, but entered sepai'ately into the 

 peribranchial cavity, thus forming two vasa deferentia. 



After its entrance into the peribranchial cavity, the sperm duct 



