46 Pub. Vuget Sound Biol. Sta. Vol. 2, No. 34> 



masses were all laid by one individual. That a given individual may stop 

 laying and begin a new mass of eggs on the same piece of eel-grass or 

 Ulva is indicated by observations on a female found at 1 1 :20 A. M. laying 

 on a piece of Ulva bearing seven other egg-masses. She stopped laying 

 when disturbed by being put into a pan. When brought into the labor- 

 atory she was again laying within 40 minutes, and on the same piece of 

 Ulva. By 12:45 P. M. she had laid a band about 1 l/o cm. long; by 2:15 

 P. M. she had laid about 4^/0 ^^ni. in all. Laying then ceased. What in 

 the natural habitat might cause cessation of laying, and again renewal at 

 a different point on the same Ulva, remains unanswered. 



In the process of laying the eggs are extruded in a flat band about 

 1 cm. in width from beneath the right side of the mantle, and pushed back 

 so as to extend posteriorly. During this process Haminea is moderately 

 extended. At intervals definite contraction of the mantle on the right side 

 occurs, at which time two or more strands of ribbon are pushed out. Due 

 apparently to a slow spiral motion of the female while in the act of laying, 

 the egg-masses are spirally coiled when of sufficient length. 



Each egg is enclosed in a comparatively large capsule, containing a 

 transparent fluid which does not become opaque upon fixation. These 

 capsules are embedded in a clear, transparent, colorless or pale yellow 

 jelly, which is in the form of a flat band about 1 cm. in width and varying 

 from a fraction of a centimeter to 6 cm. or more in length. The bands 

 are attached by their lower border to the substratum. The eggs vary in 

 diameter from 50 to 90 microns and are embedded in the gelatinous band 

 in a continuous spiral line. The eggs when collected in their masses will 

 live and develop normally for several days under laboratory conditions. 



THE UNSEGMENTED EGG 



Fertilization is internal, hence the eggs when collected had already 

 been fertilized. None were found at a stage previous to the formation of 

 tlie first polar body, and none were dissected out of the oviduct to ascer- 

 tain whether the first polar body is formed before extrusion. No unfer- 

 tilized eggs were found, and it is a question whether any are laid. 



In surface view the egg is bright yellow, with opaque yolk granules 

 scattered thruout. After the egg is laid the second polar body is thrown 

 off by the formation of a typical polar spindle (Figs. 1 and 2). The male 

 and female pronuclei approach until closely pressed together {Fig. 3). 

 No trace of the germ path was discovered in the sections at this stage, 

 which show the deutoplasm spheres densely distributed thruout except 

 for an increasing clear area surrounding the polar region. There follows 

 a comparatively rapid shifting of the yolk material, so that by the forma- 



