gested and then the meal completed with 

 the other half. 



The Testacella also resembles the tiger 

 and the shark in the possession of long, 

 fang-like teeth upon its radula. These 

 teeth are recurved and aid the mollusk in 

 getting a firm hold upon its victim, and 

 also assist in the operation of swallowing. 

 It is a curious fact that this animal will 

 not feed upon other dead animals nor 

 upon fresh meat, nor freshly-killed 

 worms. Like the snake, which it greatly 

 resembles in habits, it must hunt and kill 

 its own food. Its wanderings are noctur- 

 nal and during the day it remains con- 

 cealed, buried in the earth. Testacella is 

 quite long lived, as snails go, its duration 

 of life being about six years. 



A genus allied to Testacella, and hav- 

 ing the same predaceous habits, but be- 

 ing protected by a large shell into which 

 the whole animal can withdraw, is the 

 Oleacina or Glandina. The shell is long, 

 with a narrow aperture and a dome- 

 shaped spire ; the animal is long and nar- 

 row and the head- near the mouth is fur- 

 nished with a pair of elongated lips which 

 may be used as tentacles. The South 

 American species feed on the larger mol- 

 lusks, as the Bulimus before spoken of, 

 and the aperture of each intended vic- 

 tim's shell is carefully examined before 

 any attempt is made to enter. When our 

 "tiger" is satisfied that its victim is really 

 within, it will enter the aperture and de- 

 vour the animal. Sometimes it will make 

 a hole for itself in the shell of its victim 

 and will eat the contents through this 

 aperture instead of the natural one. In 

 Florida these animals prey upon the large 

 pulmonates like Lignus and Orthalicus. 



Before closing this brief sketch of the 

 Land Mollusks we must not neglect to 

 mention their wonderful protection 

 against the cold of winter and the heat of 



summer. This is a tough, leathery secre- 

 tion, which completely covers the aper- 

 ture, and its formation is thus described 

 by Mr. W. G. Binney in his "Manual of 

 American Land Shells." 



"Withdrawing into the shell, it forms 

 over the aperture a membraneous cover- 

 ing, consisting of a thin, semi-transpar- 

 ent mixture of lime, mucus or gelatine, 

 secreted from the collar of the animal. 

 This membrane is called the epiphragm. 

 It is formed in this manner : The animal 

 being withdrawn into the shell, the collar 

 is brought to a level with the aperture, 

 and a quantity of mucus is poured out 

 from it and covers it. A small quantity 

 of air is then emitted from the respira- 

 tory foramen, which detaches the mucus 

 from the surface of the collar, and pro- 

 jects it in a convex form, like a bubble. 

 At the same moment the animal retreats 

 farther into the shell, leaving a vacuum 

 between itself and the membrane, which 

 is consequently pressed back by the ex- 

 ternal air to a level with the aperture, or 

 even farther, so as to form a concave sur- 

 face, where, having become desiccated 

 and hard, it remains fixed. These opera- 

 tions are nearly simultaneous and occupy 

 but an instant. As the weather becomes 

 colder the animal retires farther into the 

 shell, and makes another septum, and so 

 on, until there are sometimes as many as 

 six of these partitions." 



The air-breathing snails which we have 

 so briefly discussed in this article, are 

 but a very limited number of the many 

 thousand species of this very interesting 

 group of animals. Their shells are easily 

 gathered and require but little trouble to 

 prepare for the cabinet and for study. 

 The writer, therefore, trusts that what 

 has been written may act as a stimulus 

 and induce many to take up the collection 

 and study of these beautiful objects. 



Frank Collins Baker. 



79 



