T A CHE A. 379 



which covers it. The pulmonary orifice is then opened, and a portion of the 

 air within suddenly ejected, with such force as to separate the viscid matter 

 from the collar and to project it, like a bubble of air, from the aperture. The 

 animal then quickly withdraws further into the shell, and the pressure of the 

 external air forces back the vesicle to a level with the aperture, when it hardens 

 and forms the epiphragm. In some of the European species in which the 

 gelatinous secretion contains more carbonate of lime than ours, solidification 

 seems to take place at the moment when the air is expelled, and the epiphragm 

 in these is strongly convex. 



The T. nemoralis of Europe, distinguished readily from f. hortensis by its 

 black peristome, but by many considered 



identical, does not appear to have been v ' l s- 264- 



introduced from Europe into the New 

 England States or British Provinces. 

 In 1857 I imported some hundred living 

 specimens from near Sheffield, England, 



and freed them in my garden, in Bur- "~~^ nemora u s . 



lington, New Jersey. They have thriven 



well, and increased with great rapidity, so that now (1878) the whole town is 

 full of them. They retain the habit of the species of climbing hedges and 

 trees, not remaining concealed under decaying leaves, logs, etc., like the Amer- 

 ican snails. Fig. 264 is drawn from Burlington specimens. The experiment 

 of introducing the T. nemoralis is interesting, as showing the adaptability of 

 the species to a new climate. Other species, among them Campyla=a lapicida 

 from England, and Stenogyra decollata from Charleston, South Carolina, placed 

 in my garden at the same time, disappeared at once. 



The jaw of a Burlington specimen is very strongly arched, with 4 stout ribs 

 on its anterior surface, denticulating each margin. 



For lingual membrane (see above, p. 377). 



The genitalia of the European T. hortensis is figured by Schmidt (Ge- 

 shlechts. der Stylomm., PI. HI. Fig. 15). The genital bladder is small, glob- 

 ular, on a very long and delicate duct, to which is a short accessory duct. 

 The penis sac is long, cylindrical, tapering above the insertion of the retractor 

 muscle to the point where the vas deferens enters, beyond which it has a long 

 flagellate extension. About half-way between the end of the duct of the genital 

 bladder and the common orifice is an elongate-ovate dart sac, from the base of 

 which, on either side, is a bundle of greatly developed multifid vesicles, each 

 composed in the specimen figured of four long caeca. 



POMATIA, (LEACH) BECK. 



Animal heliciform ; mantle subcentral ; other characters as in Patula. 

 Shell imperforate or subimperforate, globose, striate, horny-calcareous, gen- 

 erally banded ; whorls 4 - li, convex, the last large, ventricose, descending ; 



