254 PROCEEDINGS OF THE ACADEMY OF 



whose jaw is like that of BuUmulus.^ It seems, therefore, that 

 the lingual dentition is less reliable as a generic character than 

 the jaw, at least in cases where the aculeate marginal teeth are 

 absent. 



Finally, we are convinced that most satisfactory results will 

 ■follow the patient investigation of the jaw and lingual dentition 

 of the Geophila. i^lthough we have in many cases proved the 

 distinctions, which have been based on them, to be unreliable, we 

 believe that a further accumulation of facts will lay the foundation 

 of a natural and generally acceptable classification. 



EXPLANATION OF PLATE I. 



Fig. 1. The jaw of Helix Newherryana (see page 244). 



Fig. 2. Genitalia of Helix infumata. See references to fig. 5, 

 except 9, the duct of the genital bladder. 



Fig. 3. Genitalia of Helix Newherryana. Same references as 

 in 5, excepting 12, probably a rudimentary dart sac, for which see 

 page 245. The names of the organs are the same as used b}'' Dr. 

 Leidy in the plates of Yol. I. of Dr. Binney's Terrestrial Air- 

 breathing Mollusks of the United States. 



We failed to detect any accessory gland of the epididymis. The 

 epididymis is very long, convoluted in tlie lower half of its length, 

 straight above. It runs free for a long distance outside the mem- 

 brane which covers the oviduct, before entering into the liver, 

 where it joins the testicle. The latter is imbedded in the liver, 

 near its upper extremity. It is composed of several, apparently 

 six, separated fasciculi of blind tubes. The vas deferens enters 

 the penis about its middle, not at its end. The penis is small, 

 cylindrical. There is no trace of lobuli in the ovary, but its under, 

 concave surface is reticulated. The genital bladder is oval, its 

 duct is long, free only for a short distance, then attached to the 

 oviduct the whole length of the latter ; at its base it becomes 

 again free, and enters the vagina below the terminus of the oviduct. 

 At about the same point, the vagina receives the mouth of a long, 

 broad, rounded organ, (12 of fig. 3). This organ is hollow. Its 

 use is unknown to us, it may be a dart sac, or a prostate gland. 



1 We are about publishing this in the Ann. N. Y. Lye. of N. H., 1873, 

 X. 251, pi. xi. fig. 5. 



