No. 2.] THE OVA RJ Ay EGG OF LIMULUS. 143 



At the seven-inch stage of the animal this first oocyte has 

 formed a complete diverticulum (PI. XIV, Fig. 40). Longi- 

 tudinal sections of an ovarian tube, when it passes directly in 

 the plane connecting the point of attachment of the ovarian 

 tube and the diametrically opposite side, show a series of these 

 first oocytes all practically equal in size. 



In transverse sections of the tube, in this stage, it is seen 

 that the immediate neighbor on the right is passing through 

 the same process (PL XIV, Fig. 34) ; and this being formed, 

 two diverticula of the ovarian tube may be seen in an animal 

 about eight inches long. Now a third on the left is forming a 

 follicle in the same way. Thus the forming oocytes with their 

 follicles and diverticula appear alternately on either side of the 

 one first formed. In the thirteen-inch animal five have formed 

 and a sixth is forming ; while in the eighteen-inch stage eight 

 diverticula have been formed, the smallest being close to the 

 point of attachment of the ovarian tube. 



As these oocytes increase in size uniformly from the time 

 of their first formation, the one first formed continues to be 

 the largest, the others on either side of this being smaller and 

 smaller, corresponding to the time of their appearance, as the 

 point of attachment of the tube is approached. 



The regular sequence in which the oocytes make their 

 appearance gives to each a definite amount of space, which 

 relieves it from pressure during growth and preserves its 

 spherical form. It is readily seen, also, that this sequence 

 affords a compensation in the economizing of space in the 

 periovarian cavity ; for when the first oocyte attains to a defi- 

 nite size it is discharged ; and thus the amount of space by 

 successive discharges, as each in its turn grows, remains prac- 

 tically the same throughout. A portion of an ovarian tube, 

 taken from the living animal thirteen inches long, and exam- 

 ined under the microscope, presents the appearance of an 

 elongated cluster of grapes (PI. XIII, Fig. 16). In this way, 

 also, it can be seen that the eggs decrease or increase uni- 

 formly in size as the tube is rotated on its longitudinal axis. 



Up to this point it can be said that there exists a 

 correlation of growth between the parent organism, the 



