422 F. M. BALFOUR. 



of the parovarium — which in the female sex have developed 

 themselves to an extraordinary extent into the stroma of the 

 sexual gland, and perhaps are even to be regarded as homologiiei 

 of the seminiferous tubules (the itahcs are my own). I have 

 almost always found the above condition in the dog, only in old 

 animals these seminiferous canals seem gradually to atrophy. 

 Similar columns are present in the cat, only they do not appear 

 to grow so far into the stroma." Identical structures are also 

 described in the calf. 



Romiti gives a very similar description to "Waldeyer of these 

 bodies in the dog.^ Born also describes this tissue in young 

 and embryonic ovaries of the horse as the Keimlager.- The 

 columns described by Kulliker,-'' and believed by him to furnish 

 the foUicluar epithelium, are undoubtedly my tubuliferous 

 tissue, and, as Kolliker himself points out, are formed of the 

 same tissue as that described by Waldeyer. 



Egli gives a very clear and accurate description of this 

 tissue, though he apparently denies its relation with the Wolffian 

 body. 



My own interpretation of the tissue accords with that of 

 Waldeyer. In addition to the rabbit, I have observed it in the 

 dog, cat, and sheep. In all these forms I find that close to the 

 attachment of the ovary, and sometimes well within it, a fair 

 number of distinct canals with a large lumen are present, which 

 are probably to be distinguished from the solid epithelial columns. 

 Such large canals are not as a rule present in the rabbit. In the 

 dog solid columns are present in the embryo, but later they appear 

 frequently to acquire a tubular form, and a lumen. Probably 

 there are great variations in the development of the tissue, since 

 in the cat (not as Waldeyer did in the dog) I have found it most 

 developed. 



In the very young embryonic ovary of the cat the columns 

 are very small and much branched. In later embryonic stages 

 they are frequently elongated, sometimes convoluted, and 

 are very similar to the embryonic tubuli seminiferi. In the 

 young stages these columns are so similar to the egg tubes 

 (which agree more closely with Pfliiger's type in the cat than in 

 other forms I have worked at) that to any one who bad not 

 studied the development of the tissue an embryo cat's ovary at 

 certain stages would be a very puzzling object. I have, how- 

 ever, met with nothing in the cat or any otlier form which 

 supports KciUiker's views. 



My next stage is that of a twenty-two days' embryo. Of this 

 * 'Archiv f. mikr. Auat.,' rol. x. 



' 'Archiv f. Anatomie. Physiologic, u. wiss. Medicine.' 1874. 

 ' Loc. cit, 



