6 EXPEEIMENTS IN THE BKEEDING OP CEKIONS. 



gathered at such times and examined prove to be filled with fungal 

 mycelia, which evidently form a very large part of their food. The 

 specimens kept in captivity, however, have shown a greater range of 

 food selection; paper seems to be particularly to their liking, although 

 they will also feed upon moist commeal and other vegetable products; 

 I feel quite certain, however, that in their natural environment their 

 main diet is fungal. 



Unlike many other mollusks, instead of hiding away in moist, cool 

 places with the approach of the dry, hot day, they leave their submerged 

 position for a more elevated one, and thus placed they remain until 

 the conditions are again favorable for another foraging expedition. 

 When moving about they carry the shell almost horizontally sloping 

 backward and pointing slightly to the right. 



Mating takes place on the ground. All the specimens which I ha,ve 

 found in copulation were discovered in the early morning when the 

 conditions of moisture were ideal for Cerion activities. The mating 

 process is not a reciprocal one; that is, an animal is not actively male 

 and female at the same time, but one functions as male and the other 

 as female. The everted male organ is exceedingly long, attaining a 

 length of fully an inch and a half when completely extended. When 

 thus exposed, it reminds one strongly of a curved, flattened, white 

 bristle. 



The eggs appear to be deposited at the base of tufts of grass beneath 

 the surface of the ground and, judging from many gatherings of the 

 young in such positions, one is led to believe that a single egg onlj'- is 

 deposited at a time. I have never found more than 6 young Cerions 

 (usually 1 to 4) at the base of a single small tuft of grass, and these 

 always in different stages of growth, indicating rather long intervals 

 between oviposition. It is hoped that the experiments now in prog- 

 ress in my conservatory will throw definite hght upon this point. 



I have never found above ground young mollusks having the nepionic 

 whorls only, and by far the larger number of those having attained 

 three postnepionic whorls were dug from the sand about tufts of grass. 

 It is only occasionally that one of this size seeks the characteristic 

 elevated position of the parents. 



Our experiments have shown that it takes between 2 and 3 years to 

 produce a new generation of Cerions. We may therefore consider this 

 the time required for an individual to reach full maturity in its develop- 

 ment. No definite data are at hand so far to determine the age which 

 Cerions may attain, but many (probably most) of the specimens 

 transplanted from the Bahamas in 1912 are still in good condition 

 if not destroyed by fire or crabs. 



