420 On the Anatomical St met lire of 



(Esophageal ganglia, by two very delicate commissures, f; 

 the nerves given off by these ganglia all appear to enter the 

 walls of the buccal organ, and are all very minute. 



Genital System. The testis (fig. 5, a,) is of an oval form, 

 is not imbedded in the liver, but is loosely attached to its 

 surface. The vas deferens, b, when it reaches the under 

 surface of the ovary at b^, becomes convoluted, forming a 

 species of epididymis ; it is continued along three fourths of 

 the whole length of the oviduct, forming a glandular looking 

 band, attached to its side ; at A: it separates from the oviduct, 

 in the form of a simple tube,/, which acquires a great length, 

 and terminates in the base of the penis ; this terminal portion 

 of the vas deferens \s slightly enlarged near its commencement, 

 otherwise it is of a uniform size. The penis, g, is triangular 

 at its base, and terminates by a small cylindrical tube, in the 

 cavity common to it, and the female organs. The ovary, d, 

 and the oviduct, c c, do not differ materially from the same 

 organs in the Helices. The vesicle, e, or spermathecal and its 

 duct are closely connected with the oviduct, the vesicle itself 

 being in contact with the ovary. The length of the duct of 

 the spermatheca, is proportioned, or nearly so, to that of the 

 male organ. The male and female organs terminate in a 

 common receptacle, i, which opens externally at a short 

 distance posterior to the upper tentacles. 



Muscles. All the muscles except one, which, by their action, 

 retract the different organs within the body of the animal, or 

 the body itself within the cavity of the shell, have their origin 

 from the columella, where they are all collected into one or 

 two bundles. The buccal pouch is retracted by three or 

 four slips attached to its posterior extremity, and protruded by 

 two others (fig. 3, a a). The tentacles are each provided with 

 a retractor muscle ; also the male organ, the muscle of which, 

 as in the Helices, Achatince, and Bulimi, is attached to the 

 floor of the respiratory cavity ? 



The anatomical structure of G. truncata having been de- 



cribed and compared with some of the other genera of 



Pulmonifera, it still remains to institute a comparison between 



