HABITS, ETC., OF CEREBKATULUS LACTEUS. 135 



Furthermore, as Dr. Andrews has noted (2), the appear- 

 ance of the first body during the extrusion of the second, 

 and its subsequent changes in shape, are just what they 

 would be if the first body were pushed upward by the 

 second and at the same time held down to the surface of the 

 egg by these filaments. 



The band of protoplasm connecting the first body with the 

 egg remains after the second body is formed, and connects 

 the two bodies. The second body immediately begins to 

 elongate parallel with the surface of the egg, and assumes a 

 spindle or melon shape, which always characterises it. A. 

 small papilla now appears on the egg at either side of the 

 second|body and some little distance from it (fig. 33). These 

 two papillae are situated exactly where the long filaments 

 from the first body would strike the egg if they reached that 

 far, and it seems probable that the two are connected. The 

 papillae vary in size and number on different eggs, but they 

 are usually two. 



They are arranged symmetrically, one upon each of what 

 will soon become the first two blastomeres (fig. 34). It is 

 also significant that the spindle of the egg nucleus after the 

 extrusion of the first polar body rotates through 90°, as in so 

 many other eggs, and becomes parallel with the surface, its 

 two ends being just beneath the points where the papillae 

 afterward appear (fig. 56). 



The summits of the papillae are covered with fine spin- 

 threads, radiating outward, while the surface of the egg 

 between them is flattened or even concave. They continue 

 for about five minutes and then disappear (fig. 36). In eggs 

 not quite ripe, or developed under abnormal conditions, 

 especially pressure, the papillae are increased in number, 

 size, and duration (fig. 37). 



I have repeatedly seen unripe eggs, on reaching this 

 period in their development, put out ten or twelve large 

 pseudopodia-like processes in place of the two papillae, and 

 gradually go to pieces. 



When the papillae disappear the egg returns to its 



