No. 2.] THE OVARIAN EGG OF LIMULUS. 12I 



the fisherman's name for Limulus) is perfectly harmless so far 

 as oysters are concerned. I was delighted, however, after 

 traveling from Chicago to New Haven in order to secure 

 material late in the season, to find that they were abundant 

 on these oyster beds. 



Vitality of the eggs. — At Woods Holl, in the summer of 

 1894, the eggs, laid while the animals were observed in the act, 

 were taken from the nest as soon as the animals were about to 

 leave. The animals were also taken. Owing to the secretion 

 of the oviduct covering the eggs, they adhered more or less 

 firmly to the sand, with which they were intimately mixed, and 

 formed balls. These eggs and sand were put into a dish. No. 

 I, containing sea-water. A considerable quantity of eggs were 

 taken from the ovary of the same female, and placed in a dish, 

 No. 2 ; and, after treating them with the contents of the male 

 genital ducts, the dish was rotated ; the eggs arranged themselves 

 in a single layer, and adhered firmly to the wall of the dish. In 

 the bottom of another dish. No. 3, were placed a number of 

 glass slides, and eggs from the same source similarly treated. 

 They were fixed to the slides in the same way. In a dish, No. 

 4, eggs and sand from another nest were placed, and, like the 

 others, supplied with sea-water. Dish No. i was moved only 

 sufficiently to change the sea-water occasionally. Dish No. 2 

 was treated in the same way. The glass slides in No. 3, with 

 the eggs adhering, rested on supports, and were frequently 

 turned, so that the eggs were alternately above and below the 

 slide. The sand and eggs in dish No. 4 were vigorously stirred 

 several times a day. In all four dishes the eggs developed. At 

 the end of two months no perceptible difference, so far as the 

 development of the eggs was concerned, could be observed. By 

 means of the glass slides, the experiment of Patten ('94) was 

 confirmed; but the changes in the first indications of cleavage 

 observed by him have no perceptible influence on the develop- 

 ment of the egrgs. 



The above experiments were begun on June 25. The eggs 

 were not exposed to sunlight, and the development was slow 

 and irregular. On the first of September many of the embryos 

 had hatched, while many of the eggs showed no sign of devel- 



