MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 175 



yolk, in which the large nucleus is Located. Over this region of the ovum the ridges are absent, 

 while those which lie at the margin of the area form incomplete meshes open on the side toward 

 the egg nucleus. 



The clear polar area of the ovum is approximately triangular, " and from each of the corners 

 of the triangle what may he called a line of weakness occurs in the follicular wall, bound on 

 either side by incomplete meshes." (Willbt.) 



"The yolk is viscous and glutinous, and posseses a translucent brownish tinge. The nearly 

 ripe ova rupture with the utmost facility." (AYilley.) 



•• In the female tin 1 ramifications of thegenital artery pass up on to the surface of the individual 

 ova. and form a kind of capillary system, the finer branches following, but not always confined 

 to, the reticular markings formed by the ridges of the follicular membrane which project into 

 the yolk. The arteries which traverse the surface of the ova give off minute branches which 

 pass inward, as it were, into the depths of the follicular ridges; and these deep-lying vessels 

 anastomose with one another, while the superficial branches appear, as a rule, not to form anas- 

 tomoses. It may be added that the impression of anastomoses is much more readily conveyed 

 by examination with a hand-lens than it is by the use of the compound microscope." (Welley.) 



The epithelium about the mouth of the ovary is composed of columnar cells bearing long 

 cilia; farther within the ovary the epithelium gradually passes from columnar to cubical cells. 



Kefersteix 1 and Lankester and Bolrnk have figured a large albumen gland attached to 

 the ovary near its mouth. This has the shape of a large sac, of about the same volume as the 

 ovary, lying upon the right side of the latter. Bourne's diagram may be simply a copy of 

 Kefersteix's figure; nothing in the text gives any information as to whether the authors had 

 seen the albuminous gland in their own dissections or not. 



No other authors describe such a structure. I have myself been unable to find any traces of 

 it in several female Nautili 1 have dissected. In several cases I have found the ovary filled with 

 a hard, solid, brown coagulum. probably secreted by the walls of the ovary. As in one of 

 the specimens dissected all the large ova had just been shed, this specimen was certainly sexually 

 mature. If the gland is only formed periodically, we should certainly expect to find it in such a 

 specimen. It is probable that the ovary of Keferstein's specimen was abnormal and possessed 

 a hernia-like protrusion. 



Haller has previously noted the absence of such a structure as Keferstein figures and has 

 come to the conclusion that the ovary of Keferstein's specimen was in a pathological condition. 

 Some of Hali.er's specimens also had the ovary tilled with the secretion already mentioned, of 

 which he speaks as follows: "It has the same appearance as the egg-yolk, staining similarly 

 with certain stains (carmine) or remaining unstained with others (hematoxylin). This yolk is 

 the same as that in the eggs, from which I distinguish it by the name of the free yolk, and is 

 used by being taken into the eggs. At first I thought that it might possibly be composed of an 

 accumulation of yolk cells, but nuclei could not be discovered in it by means of the various 

 nuclear stains used, it being a homogeneous mass — a secretion from cells. I then sought for a 

 glandular differentiation, which, as processes of the ovarial wall, might project inward and 

 function in the secretion of the free yolk. However, there was no such structure present, and 

 nothing remains but to hold the portions of the wall of the ovary which are free from eggs 

 responsible for the production of this yolk. It is probably the right lateral side of the ovary, 

 upon which I have never found eggs, which performs this secretion. 



•"The cells of this portion of the ovarial wall would not, then, function as germinal epithelium, 

 but would furnish a sort of nutrient material, not by giving off cells, but instead, pure yolk- 

 stun'. The histological structure of that portion of the ovarial wall seems to me to indicate this. 

 I found there a layer of cells, the elements of which were in all things very much like the follicle 

 cells: it is composed of high cylindrical elements, which are completely tilled with yolk granules. 

 In places, where the cells had been separated from each other by shrinkage caused by alcohol, 

 one could observe numerous protoplasmic connections between them. The cell nuclei are, like 



'Bronn's Classen und Ordnungen. 



