Some Observations on the Chromosome Vesicles in the Maturation etc. &9 
united, probably with mucous, so that the animals may be pulled 
about in the aquarium with considerable freedom without causing 
them to separate. I took a pencil and pushed one animal of a pair 
all around the dish but they did not separate until the irritation 
became extreme. When they are copulating the distended and 
swollen ends of the oviducts as they are united are spherical in 
form and the color is intensified. So close is the union that I could 
not detecet the line of fusion. The distended end of the oviducts 
after copulation .is gradually withdrawn into the body until the 
animal presents a normal appearance; this reduction took nearly 
three hours in one instance.« 
»The egg-mass of M. pilata is laid in the form of a string 
which in some instances was at least six inches long. This string 
of eggs is more often undulating than straight. There are from 
two to eight eggs in a single section of the string. No attempt 
was made to determine the whole number of eggs laid by one ani- 
mal. The animals in confinement frequently laid short strings of 
eggs, one to three inches in length and laid several times. Depo- 
sition oceured from twelve to twenty-four hours after copulation. 
The rate of development of the eggs is the same as D. bifida. 
Methods. No diffieulty was experienced in securing properly 
fixed material by the use of KLEINENBER@G'S piero-sulphurie fluid, Bo- 
VERT’S piero-acetiec, and GıLson’s mixture; although the latter gave 
the least satisfactory results. Many of the spawn masses of M. 
Gouldii were very diffieult to section when fixed by either of the 
above reagents. The following stains were used: HEIDENHAIN’s 
Iron haematoxylin accompanied by a plasma stain of Bordeaux red, 
CoNKLIN’s piero-haematoxylin, and Brazilin. Each have their especial 
value, the first two being used on all of the stages deseribed in this 
paper. So tenaciously does not only the deutoplasm but also the 
cytoplasm retain the Iron-haematoxylin stain, that it was impossible to 
secure a differential stain by its use alone. The eggs of the two 
species of Montagua are very diffieult to stain satisfactorily. The 
'eggs were imbedded in paraffine at 53 degrees F. but left in the 
warm paraffine only thirty minutes which was found to be adequate 
for penetration and did not cause the eggs to become friable. 
Ovocyte. Sections of the ovotestis of each of the three species 
shows the ova in all stages of development. The young ovocyte is 
free from deutoplasm, the eytoplasm presenting a granular appearance, 
homogenous throughout. The increase in size is accompanied by the 
