KtTNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 63. N:0 9. 9 



the inner follicle, within which the test-cells are to be seen all around. Bebind the 

 embryo lies the empty follicle still connected with the walls of the brood-pouch; the 

 lumina are still in commimication with each other, the egg having just removed from 

 the one cavity to the other. The follicular epithelium, as well as that of the oviduct — 

 traces of which are to be observed at the margin of the opening — is highly contracted. 

 It may be assumed that, before bursting, they were subjected to strong tension owing 

 to the growth of the ovum, and that the contraction into the present shape commenced 

 as soon as the ovum had entirely passed out of the follicle. On account of this con- 

 traction it is also to be assumed that the entrance into the brood-pouch became closed, 

 whereupon the follicle was cut off from the latter and immediately began to degenerate 

 (ef. text-fig. 4). In some individuals a very small vesiele of conical shape has been 

 observed connected with the bottom of the brood-pouch. That may perhaps represent 

 a vestigial trace of the oviduct. 



Text-fig. 4 shows a section made through the brood-pouch and the embryo in a 

 more advanced stage of development. The brood-pouch is of globular form ; it is 

 enclosed in a dilatation of the body-wall. As is evident 

 from the figure, it is a diverticulum of the peribranchial 

 cavity, with which it still communicates through a well 

 marked-off but short canal. The epithelium in its wall 

 is low. It encloses an embryo in a late stage of division, 

 surrounded by the inner follicle and test cells. 



As has been mentioned above, the brood-pouch 

 develops as a direct projection from the peribranchial cavity. *£** &£?!££$?%?££. 

 This observation of mine does not agree with that of pouch containing an embryo, xiic. 



bp. Brood-pouch. ec. Ectoderm. em. 



MlCHAELSEN, wllO giveS a deSCription Of the StrUCtlireS Embryo, op. Opening of the brood- 



.. " , , ., . ,, pouch. p. Outer wall of the peribranch- 



in question apparently at the same stage as the one iai cavity. 



described above. He reports »eine die Leibeswand weit 



ausbeulende — — — Kapsel von X U mm Dicke, etwas grösser als eine einzelne 

 Hodenblase. Diese Kapsel enthält einen — — Embryo in ziemlich friihen Ent- 

 wickl ungsstadium. — — — Vom Grunde der Kapsel ragt eine winzige, meist becher- 

 förmige Wucherung sehr kleiner Zellen in das Lumen hinein, die zweifellos Ueberreste 

 von Ovarien darstellen. Sonst ist an diesen ausgewachsenen Personen nichts zu 



finden, was als Ovarien anzusprechen wäre — . Ich glaube - annehmen 



zu sollen, dass die sich sehr friih in den j ungen Knospen bildenden Ovarien durch 

 die sich später an den ausgewachsenen Personen bildenden Hoden nach hinten gescho- 

 ben werden und nur je einen einzigen Embryo zur Entwicklung bringen, während die 

 iibrigen Ovarial-Zellen teils zur Bildung der Brutkapsel, teils zur Ernährung des 

 Embryos verwendet werden» (1. c. p. 106). It is rather difficult to make out the 

 meaning of the expression »becherformige Wucherung». It is not applicable to the 

 empty follicle, i. e. the corpus luteum-like strueture, which does not project into the 

 lumen of the brood-pouch, nor to the stalk of the brood-pouch connecting the latter 

 with the peribranchial cavity. Nor is it clear what corresponds to the bottom of 

 the capsule described. The statement that the brood-pouch is formed of 



K. Sv. Vet. Akad. Harull. Band 63. N:o 9. 2 



