KOFOID: DEVELOPMENT OF LIMAX. 37 
II. METHODS. 
The most successful method of keeping the animals in captivity was 
found to be as follows. A tin box with proper ventilation is filled to 
the depth of one inch with olean sand, which forms a suitable substratum 
for the retention of moisture. On this is laid down a sheet of moss, to 
whose under surface the earth still adheres. The leaves of the common 
plantain furnish acceptable food, and, when this is no longer available, 
fresh cabbage leaves and apple parings can be used. The eggs, which 
seem more often to be laid at night, are found in clusters in the soil, or 
cunningly packed away in the moss itself. The rate of development is 
such at the ordinary temperature of the labo ratory that the eggs col- 
lected in the morning will generally be found to havo already reached 
the early stages of cleavage, while gastrulation progresses during the 
second day, and is completed early in the third. During the first week 
of captivity the slugs furnish eggs in great abundance; but after that 
time the number diminishes and the quality deteriorates so rapidly that 
it is imperative that a new colony be secured. Abnormalities in the 
living egg show themselves in the early stages by a loose assemblage of 
the cells, and the increasing opacity of the embryo, 
Before hardening the embryo, it is necessary to free it from the en- 
velopes and albumen which surround it. As the eggs of Agriolimax 
agrestis aro much smaller than those of Limax maximus, it was not 
possible to employ the method deseribed by Miss Henchman ('91) for 
shelling the eggs. But by inserting two fine cambrie needles in one 
holder, so that the distanee between the points is less than the diameter 
of the unshelled egg, it is possible to hold the egg between these two 
needles and pierce it by a third. A quick shear-like cut with the third 
needle against one of the other two tears open one side of the egg and 
allows the albumen aud the ovum to escape from the envelopes. It is 
very desirable not to entangle the embryo in the viscous matter between 
the inner and outer envelope, for it is almost impossible to remove this 
when it is once attached to the embryo. The albumen interferos with 
section-cutting and obscures whole preparations, so that it is necessary 
to remove it entirely. "This for a long time presented a most serious 
obstacle to my work. Washing off the albumen with water is a very 
slow and tedious process, and not always successful. Some of the eges, 
after treatment with Merkel's or Flemming's fluid for a short time, were 
washed with hypoohlorite of soda to rid them of the albumen. The 
