220 CLA YPOLE. [Vou. XIV. 
an adult, recently hatched young, and several stages of em- 
bryos are figured and described. All of Ryder’s studies were 
made on whole specimens, and none of the early stages were 
figured. 
The material was collected mostly during the summer of 
1895 at Woods Holl, Mass., in connection with work done at 
the Marine Biological Laboratory. Both animals and eggs are 
found under stones, on sandy beaches, at about the level of 
half-tide, so that they are completely submerged for about half 
thetime. They would thus be submerged to a maximum depth 
of about eighteen inches of water, the average tide being three 
feet in height. 
Different methods of killing and preserving eggs and adults 
were used. The most satisfactory for the eggs proved to be 
the simple process of killing in hot water and hardening first 
in 70% and then passing to 95% alcohol. Owing to the thick 
membranes surrounding the ova, other processes failed for lack 
of penetration and resulted in shrinkage and distortion. Adults 
and young ones were killed in hot water and hardened in the 
same way as the ova; those killed and hardened in warm and hot 
corrosive-acetic and picro-acetic acids and kept afterwards in 95% 
alcohol gave very good results. Owing to the difficulty experi- 
eenced in wetting them, any method involving an early applica- 
tion of alcohol was easier than using water solutions entirely. 
Hot solutions were found better than warm, as they prevented 
contraction, causing the animals to die stretched out straight. 
The material was almost all cut in hard paraffine and stained 
on the slide variously with borax carmine, Erlich’s haematoxy- 
lin, lithium carmine and Lyon’s blue, iron haematoxylin and 
orange G. Double staining was chiefly used and a few tests 
made with Biondi-Erlich. Sections were cleared in xylol and 
mounted as usual. In thickness they varied from five to 
fifteen micra. 
Structure of Adult Ovary. 
In specimens in which the eggs are nearly mature the struc- 
ture of the ovaries is much obscured, as the abdomen appears 
to consist of a mass of eggs closely packed together and hence 
