Ovum and fætal membranes of Lagenorhynchus acutus. Gray. 



Vi'^. \. Tlie entire ovum of Lagenorhynchus acutus, Gray, containing the 8 uiillim. long embryo. Natural size. Two 



parts are observable, corresjionding to the two uterine horns. 

 2. Tlie same ovum opened. Natural size. Drawn by I)r. F.Nansen. o»h = amnion with embryo; «// == allantois, 



the broad part of it; ch = chorion; h = vesicle-like formations; I; = vessel; M = conical thickened part 



of a vessel. 

 _ 3. Part of the same ovum, enlarged 4 times. Drawn by Olaf Bergh. All = the expanded, leaf-like portion of the 



allahtois covering the amnion with the embryo; AW = the opposite, thinner end of the allantois; ch = chorion; 



/■ = vessel. To the left of the allantois projects the umbilical vesicle. On its right, three vesicle-like formations. 

 4. Part of the same ovum, magnified 4 times. Drawn by Olaf Bergh, am = amnion enveloping the embryo: the 



amnion contains numerous vessels, h = vesicle-like formations; r. u = vesicula umbilicalis. 

 .5. From the same ovum. The coarser distribution of vessels in the chorion (magnitied). Drawn by Dr. F. Nansen. 



6. Vesicula umbilicalis from the same ovum, magnified; drawn by G. Guldberg, after it was detached from its 

 connections. On the surface are seen small protuberances, which are indicated in the drawing by darker stripes 

 and patches. 



7. The 30 millim. long foetus of Lagenorhynchus acutus. Gray, twice the natural size. Diawn by H. Bucher. 

 jun. The fcetus is enveloped in the amnion, in which fine vessels are seen; parts of the chorion and allantois are 

 adhering and rolled together. The dotted lines indicate where the amnion and the allantois were coherent. 



8. The 4.0 niillini. long fictus of Lagenorhynchus acutus. Gray. Natural size. Drawn by H. Bucher. jun. 

 The fcetus is lying in the amnion. A portion of the other foetal membranes is attached, The longitudinal stripes 

 on the amnion are folds. The dotted, obliijuely transverse line shows the place where the amnion and the allantois 

 were attached to each other. 



