16 AMERICAX JOURNAL 



radula is much narrower and contains fewer teeth. The same 

 generalization holds good in regard to the individual teeth. The 

 larger the number of denticles on the cusp, the greater the ten- 

 dency toward variation among them. In working over the den- 

 tition of the Pulmonata, especially, it is very desirable that as 

 large a number as possible of ribbons of each species should 

 be compared to correct such errors of variation from the normal 



The main point of the cusp in the inner laterals is about twice 

 as long as the base ; it becomes proportionally shorter toward 

 the edges of the radula. 



All the denticles or teeth of the cusps are sharply pointed. 

 About the seventy-fifth lateral the edges of the cusp on each 

 side of the prominent denticle are slightly notched, and the two 

 small denticles are almost evanescent. These notches disappear 

 about the one hundredth lateral, and the long tooth gradually 

 decreases in proportional length, until in the extreme outer 

 laterals it is not more than half as long as the base. 



The oesophagus leaves the buccal body above and before the 

 posterior extremity of the latter, and is slightly dilated there. 



It enters the ventral side of the stomach with a short double 

 flexure. The stomach is oval in shape, and in all the specimens 

 dissected was filled with a dark green vegetable matter. Leaving 

 the stomach at the posterior end, the intestine turns upon itself 

 and passes over the superior surface of the liver, diagonally 

 across the body, terminating just inside the opening in the mantle. 

 The sinus in the shell is due to the anterior extremity of the 

 lung, and does not quite correspond with the course of the rec- 

 tum. The latter half of the intestinal canal is divided interiorly 

 by incomplete septa, which serve the purpose of expelling the 

 faeces in oval pellets. 



Reproductive System. The ovary is situated to the right of, 

 and below the stomach. It consists of a number of convoluted 

 tubes, more or less spirally twisted upon each other. The ovi- 

 duct is short, and provided with an accessory mucous gland. 

 Near the anterior extremity of this a small muscle is attached, 

 and is fixed at the other end to one corner of the nearly triangu- 

 lar vagina. The uterus is a kidney-shaped organ, and the duct 

 passing from it into the vagina is provided with a genital bladder 

 as in other Pulmonates. The vagina terminates in a small pa- 

 pilla externally. In small specimens this is almost invisible. 



The exact extent of the testicle was not clearly made out, but 

 it is very slender and situated at the posterior end of the animal, 

 in or upon the surface of the liver. 



The vas deferens is long and slender, passing through a pear- 



