KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 63. N.O 2. 53 



From the above-mentioned facts one might conclude that the members of the colony 

 do not attain sexual maturity at the same time, probably owing to different age. 

 As appears from figs. 48—49 the part of the genital pouch which contains the genital 

 organs 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 deve- 

 lopment of the brood-pouch, as will be described in the following. 



The male organ. 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. The spermatio 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 (ef. Pl. 3, 

 figs. 50 & 54). 



In one individual examined another arrangement was observed. Here the two 

 duets did not join, but entered separately into the peribranchial cavity, thus forming 

 two väsa deferentia (ef. Pl. 3, figs. 51 — 52). 



After its entrance into the peribranchial cavity, the sperm-duct generally bends 

 somewhat to the side, extending along the inner wall of the cavity. This arrange- 

 ment was observed in all specimens but one. In the latter, a rather large individual 

 with a strongly developed testis, the distal part of the vas deferens was coiled up, 

 and its opening lies close to that of the brood-pouch (ef. Pl. 3, fig. 56). As this 

 arrangement has been found in a single individual only, I do not venture to draw 

 any conclusions from it. The possibility seems, however, not excluded, that it might 

 be of some importance for the fertilization, in this case probably the self-fertilization 

 of the individual. The iact that ova and spermatozoa are not seldom found mature 

 at the same time in the same individual appears also to support the view that self- 

 fertilization can take place; whether it is usual is another question. 



From sections it appears that, in zooids belonging to colonies caught in June, 

 masses of spermatozoa fill up the sperm-ducts. Other cells are macerated, but the 

 spermatozoa are in good condition — a fact which confirms the observation made 

 many times before that the spermatozoa are more resistant than other cells, and 

 that they are highly resistent, even to maceration. 



The fe male organ. In zooids most advanced in development the female 

 organ consists of a small ovary with a wide oviduct and a very large brood-pouch. 

 As is shown by fig. 53, a small rounded vesiele with a wide duct is situated at the 

 side of the male glands in the genital pouch. Sections through it did not show much 

 of its strueture, the tissues being rather macerated. The presence of eggs makes it, 

 however, evident that this strueture is to be regarded as an ovary. (Pl. 3, fig. 54.) 

 Whether it is an ovary in the proper sense of the word, is another question 

 which will be discussed in an artide on the Botryllids which will soon be published. 



As mentioned above, the ovary is placed at the side of the male glands and 



