No. 2.] THE OVARIAN EGG OF LIMULUS. 175 



be essentially the same. Immediately beneath the first layer 

 of the chorion a homogeneous layer of protoplasm appears (PI. 

 XIII, Fig. 13), which does not stain so deeply as the more gran- 

 ular protoplasm which it surrounds. In favorable preparations 

 this layer appears to be composed of fibers which resemble 

 those of the cytoplasm except in the absence of the conspicu- 

 ous cyto-microsomes. The fibers are at first arranged more or 

 less perpendicularly to the surface of the egg (PI. XIII, Figs. 13, 

 18). At this stage they present the appearance of regularly 

 arranged cilia, covering the surface of the egg, and they are 

 imbedded in a transparent substance which solidifies into the 

 inner layer of the chorion. 



The radial striations so conspiaioiis in the chorion of Limulus 

 £ggs are therefore due to protoplasviic fibers. Originally, at 

 least, the radial striations are not due to radial pores, as is so 

 frequently asserted of other eggs. The process appears to be 

 practically similar to the formation of chiton and other cutic- 

 ular substances by the fusion of cilia. The shining pores 

 previously mentioned in connection with the primary egg cov- 

 ering and the peripheral bodies (PI. XIII, Fig. 18; PI. XIV, 

 Fig. 28) are either transverse sections of these fibers or their 

 points of insertion. As we have seen, the outer primordial 

 covering, — tunica propria, — which is the original basement 

 membrane of the germinal epithelium, arises in essentially the 

 same way as a cuticular hardening of the outer ends of the 

 epithelial cells. 



The peripheral bodies, which in their earlier stages resemble 

 nuclei, call to mind the so-called " Binnen " epithelium of 

 Eimer ('72), which figured so prominently in the discussions 

 concerning the cell nature of meroblastic eggs, and may pos- 

 sibly explain the much disputed observations of Clark ('57) in 

 the ovarian egg of the turtle. They may possibly be compared 

 to the bodies observed by O. Schultze ('87) and Goette ('75) in 

 the peripheral layer of amphibian eggs, and I believe they 

 ser\'e to explain the observation of Schiitz ('82) in the egg of 

 spiders. So far as I am aware, he is the only student of those 

 eggs who has claimed the existence of a follicular epithelium 

 surrounding them. Bruce ('85) and Brooks ('86) have shown 



