82 TERRESTRIAL AIR-BRKATHING MOLLUSKS. 



pouch capable of a proboscidiform protrusion, the aperture furnished with 

 three pupillu; above and three on each side, (ienital orifice at some distance 

 behind the right eye-peduncle. Anal and respiratory orifices on the right of 

 the mantle, under the peristome of the shell. Mantle thin, posterior, covered 

 by a well-developed shell. No distinct locomotive disk. No caudal mucus 

 pore. 



The eggs are eight millimeters long, covered with a hard calcareous shell. 



The subgenera Varicella and Oleacina, a. str., are not found within our limits, 

 but only the 



Subgenus GLANDINA, s. str. 



Shell ovate, or ovate-oblong, plicately striate, generally of a silken lustre, 

 but never glittering, and usually decussated with delicate revolving lines ; 

 suture crenulated ; aperture equalling about half the shell's length, its peri- 

 stome simple. 



Jaw absent. Lingual membrane narrow, with chevron-shaped rows of uni- 

 form, aculeate, separated teeth ; central tooth with a long, slender, straight base 

 of attachment, with incurved sides, and with inferior lateral slightly expanded 

 angles, and with the upper margin reflected and extended into a long, slender, 

 acutely pointed cusp. There are no lateral teeth, the balance of the mem- 

 brane being composed of marginal teeth of the pure aculeate form. 



Each roAV of teeth on either side of the median line curves first backward, 

 with the teeth rapidly increasing in size as they pass outwards, and then for- 

 wards as the teeth gradually again become smaller; giving an irregularly 

 crescentic shape to the, half-row of teeth. This is shown particularly in Gl. 

 Albersi and G. rosea, less so in GL truncata. The central tooth was overlooked 

 by Wyman, Leidy, and other of the earlier investigators. It has since been 

 detected in GL truncata,^ rosea,^ algira,^ Sowerbyana* pUcatula,^ fusiformis,'^ 

 Albersi''; in semitarum,^ Phillipsi^ of the subgenus Varicella; also solidula'^^ 

 of subgenus Oleacina. This central tooth is rather diflicult to study, being on 

 a different plane from the other teeth, and apparently much less developed. 



1 See L. & Fr.-W. Sh., I. Fig. 6. 



2 Amer. Journ. Conch., V. 202, Fig. 1. 



8 Fischer and Crosse, J. de C, XV[. 234, 1868 ; Moll. Mex. et Guat., PI. IV. Fig. 10. 

 * Same, Moll. Mex. et Guat. 73, PI. IV. Figs. 6-9. 

 6 Ibid., p. 73. 



6 Ibid. 



7 L. k Fr.-W. Sh., I. Fig. 10, p. 19. 



8 Proc. A. N. S. Phil. 1874, 49. 



9 Ibid. 



10 Ann. Lye. N. H. of N. Y., X. 347. 



