PART II. 



HELICINJE. 



333 



Gonospira Sw. Spire perfectly cylindrical, of equal 

 thickness, the tip obtuse, with the whorls large ; aper- 

 ture oval ; lips thickened ; pillar with or without a 

 plait. 



G. polanga Desk. Lesson, Voy. pi. 8. f. 8. 



Megaspira Lea. Spire excessively long, of more than 



twenty volutions, and of nearly equal thickness ; the 



tip persistent, and slightly pointed; aperture rounded; 



outer lip thin ; pillar and inner lip with sharp plaits. 



M. elatior Spix. Test. Braz. 15. f. 1. 



Siphonostoma Guild. Spire excessively long, pointed, 

 but the upper portion deciduous ; aperture circular, 

 spreading ; the lips united, and detached from the 

 adjoining whorl, (fig. 97. c, rf.) 

 S. costata Guild, (fig. 97. c, d.) 

 fasciata. En. Meth. 461. f. 7. 



HELICELLA Feruss. Shell discoid, 

 but the body-whorl thick and 

 ventricose ; the spire very small 

 and sunk ; pillar none ; aperture 

 semicircular ; outer lip thickened; 

 umbilicus very wide, (fig- 98.) 

 pellis-serpentis ( fig. 98.); also Fer. 

 Mollus. pi. 66. 73. 75. 77. 



