No. 2.] THE OVARIAN EGG OF LIMULUS. 123 



and the point of anastomosis of the right and left branch, each 

 of these branches gives off a large secondary branch (pv.t), 

 which passes backward on the right and left side of the ali- 

 mentary tract to the anus (an). These are not simple tubes, 

 however, as has been affirmed by Owen ; but rather a network 

 of anastomosing tubes which surrounds the alimentary tract, 

 nearly concealing it, except immediately over that part of the 

 operculum where the external openings are situated {g-o.). 

 The lateral tubes of this system when filled with eggs are 

 larger than the tertiary branches above and below. 



After anastomosing in the median line the two secondary 

 branches previously described again separate, and, retaining 

 approximately their original size, pass forward on each side of 

 the alimentary tract {al.c), along the adductor muscles (;;/.), in 

 the meantime sending smaller anastomosing branches over 

 the alimentary tract, and large branches between the muscles. 

 Finally they unite again in the anterior part of the cephalo- 

 thorax immediately over the oesophagus. 



The right and left peripheral branches of the divided oviduct, 

 retaining for some distance the original dimensions, proceed 

 outward, slightly backward and downward, giving off, close to 

 the adductor muscles, a large branch. This passes along the 

 muscles to the right and left of these till they become united 

 in front of the adductor muscles to the tubes previously 

 described. They again give off branches passing between the 

 adductor muscles toward the central axis of the body ; and 

 these unite with the corresponding tertiary branches proceed- 

 ing from those running parallel with the intestine previously 

 described. 



This system of large tubes lying over the alimentary canal 

 and surrounding the adductor muscles has been described by 

 Owen ('73) as the ovary of Limulus. 



In the further course of the peripheral branch of each of 

 the secondary branches numerous tertiary branches are given 

 off. The whole finally resolves itself into a number of small 

 tubes that anastomose with their neighbors and with tertiary 

 branches given off from the large system of tubes surrounding 

 the adductor muscles. Thus the whole ovary becomes a net- 



