( ('^^ ) 



iimbilicalia. As far as I know, a case of tlio presence of vasa propria 

 funiculi in any animal was not on record. 



This isolated case suggests tiie general peculiarity of the \'ascular 

 system of seals, to which attention has already been drawn by 

 Hyrtl^). I may add tiiat the immediately surroundin.ü; pai'ts of the 

 allantois were also very rich in vasa propria, whicii, however, were 

 generally of smaller size. 



A microscopic examination of tlie chorion, or rather ofthewallof 

 the outermost and widest emI)iTO-sac, shows us that thei'c arc two 

 layers, an outer one and an ijiner one, connected by exti-emely 

 loosely woven cellular tissues ; between the two layers the blood- 

 vessels are situated. The outer, or uterine layer, the chorion proper, 

 is lined with a simple cylindrical epithelium about 20 (i high. The 

 nuclei are o\'al-shaped and in the basal half of the cell ; the proto- 

 plasm is finely granulated. Cell limits ai'c distinctly visil)le. The inner 

 lininir consists of one laver of flat cells with much-llattened nuclei. 

 The inner coat is nothing but the outer surface of the allantois. 

 (This connection u ill be i-eferred to bye and bye). We caimot, there- 

 fore, call this membrane the choi-ion, sti-ictly speaking, the name of 

 outer foetal envelope is more to the [)oint. The bloodvessels in the 

 wall of this sac are of unequal calil)er, in the centre, between the 

 two lavers, larger vessels are met with, the arteries have a thick 

 muscular coating, smaller vessels arc found partly in the stroma of 

 the allantois, in greater quantity however right under the chorion- 

 ectoderm. 



Even with the naked eye an accumulation of small \i\\i, conspi- 

 cuous by their velvety as])ect, could be seen in some places on the 

 nterine surface of the outer foetal sac. A microscopic examination 

 confirmed that these were rudimentary xilli. The epithelium did not 

 differ from the other parts, but the stroma was a much more com- 

 pact tissue and the interior was filled with very numerous capillaries 

 the central ones of Avhich had a fairly large Inmen. 



The amnion, too, or rather the inner foetal sac, is found to consist 

 of two layers, lying against each other along the Avhole surface; only 

 where the uml)ilical vesicle is situated they separate to envelop this. 

 The inner layer is covered with a cubic epithelium of 10 |!i., the outer 

 one is identical with the inner layer of the outer foetal sac and 

 must be considered to be a layer of the allantois. On comparing 

 foetal sacs of Phoca vitulina with those of other carnivores, Phoca 



1) Hyrtl. Ueber einige Eigentümlichkeilen der arterielleii Gelassveriistelungen bei 

 den Seehunden. 



Sitz. Ber. d. malli. naluiw. Classe d. Akad. d. Wissensch. Vienna. Bd. XI. 1854. 



