184 GENERAL ZOOLOGY 



the eye-stalk; others are inclined to think that the animal 

 has a more definite organ of smell in the osphradium. This 

 organ occurs on the mantle-edge near the lung-aperture. 



The ravages of Limax maximus are not serious, if the 

 florist does not allow refuse to collect about his buildings. 

 Many adopt the method of scattering ashes or cinders about 

 the plants to be especially protected. A slug crawling into 

 such an obstruction is stimulated by the dryness of the ashes, 

 or the roughness of the cinders, to secrete mucus from the 

 glands that occur in the skin. This mucus is like that which 

 is secreted from its foot-gland while crawling. Owing to the 

 unusual amount of mucus given off at such times, the animal 

 dies from exhaustion, and from suffocation by the drying of 

 its skin. 



From the beginning of September to the end of November 

 Limax maximus lays its eggs in its place of hiding. The eggs 

 have about one half the diameter of dried peas. They are quite 

 spherical. The shell is translucent and is tough and membra- 

 nous. Twenty-five or thirty eggs are deposited at one time, 

 and left on the ground in a loose, agglutinated mass. The 

 embryos of the early eggs hatch within two or three weeks, 

 while eggs deposited late probably do not hatch until the 

 following spring. The garden-slug is hermaphroditic. The 

 eggs and spermatozoa in each individual mature at differ- 

 ent times, and consequently the union of two individuals is 

 necessary for the fertilization of the eggs. 



Garden-slugs that live out-of-doors burrow into the ground 

 and curl up when the coldest weather comes. Those in green- 

 houses remain active throughout the year. 



The Oyster-Drill. A few minutes' walk along almost any 

 pebbly beach between Florida and the Gulf of St. Lawrence 

 would afford a collector the opportunity of observing the sub- 

 ject of this description, the oyster-drill (Urosal'pinx cine'rea, 

 Fig. 99). In such a walk the artist discovered the unfortunate 



