linville: pulmonate gasteropods. 215 



Limax maximua may be found in the vicinity of Cambridge in damp, 

 protected i)laces, under rotting wood, or under waste lumber and straw, 

 and especially about greenhouses, where these slugs, and also Limax 

 agrestis, are found most abundantly. The eggs of Limax maximus are 

 not covered with earth, as are those of Limax agrestis. It is seldom 

 that one finds the eggs of Limax agrestis lying exposed on the surface of 

 the ground. Limax maximus in captivity apparently lays its eggs wher- 

 ever it happens to be ; sometimes on the bare side of the box or can in 

 which it is confined ; at other times under a piece of rotting wood or 

 other protection. Limax agrestis, on the other hand, almost invari- 

 ably bores into the loose soil in the box, sometimes nearly an inch, and 

 lays its eggs in a single heap. Its eggs do not cohere as do those of 

 Limax maximus. 



In general, early morning is the time when eggs are laid by both 

 species of Limax, although the laying may take place at any time of 

 the day or night. The duration of the time of laying is not great. IN"© 

 continuous observations of the time consumed in laying were made, 

 because of the desirability of getting eggs in as early stages as possible, 

 the animal being killed as soon after the beginning of laying as possible. 

 Considering the time required to extrude several eggs one after 

 another, however, it does not seem likely that more than thirty minutes 

 w-ould be required to complete the extrusion of the largest number 

 deposited at a single laying. 



About the 15th of March, 1897, I collected a large number of Limn?ea 

 elodes Say, one of the common pond snails. Many pairs were found in 

 the act of copulation. In the course of two days eggs were laid in the 

 aquarium in great abundance. These snails can be stimulated to lay 

 simply by supplying plenty of fresh water and keeping the vessels free 

 from any decaying matter. Laying usually takes place early in the 

 morning, but a sudden change from impure water to pure water will 

 cause them to lay at any time of day. 



Technique. 



The eggs of Limax were taken either just after laying or from the 

 sexual organs, before being laid. The latter were obtained from the 

 uterus, from the albumen gland, or from the oviduct. The eggs just 

 deposited and those abstracted from the uterus, where they lie one after 

 another ready to pass to the exterior, were " shelled," freed from the 

 albumen and fixed. The albumen gland and the oviduct of individuals 



