EXPERIMENTS IN THE BREEDING OF CERIONS. 31 



Table 13 indicates merely that we have in this Florida-grown mate- 

 rial a very slightly larger range of variation, but no difference in type. 

 The largest number of whorls observed in any member of this genera- 

 tion is 12 mm. and the least 8.9 mm. In the check series we find 11 

 mm. and 9.1 mm. The largest altitude observed in this generation was 

 27.9 mm. and the smallest 18.7 mm., while in the check series the 

 largest was 27 mm. and the smallest 19 mm. The greater diameter 

 of our Florida-grown material was 13 mm. and the least 8.8 mm., 

 whereas in the check series we obtained 12.7 mm. for the largest 

 measurement and 9 mm. for the least. A comparison of the average 

 measurements of all the Florida-grown first generation material with 

 the average measurement of the check series presents the following: 



Number of whorls, 10.16 for the Florida-grown specimens and 10.08 for the check series. 

 Altitude, 22.84 mm. for the Florida-grown generation and 22.56 for the check series. 

 Greatest diameter, 10.74 mm. for the Florida-grown specimens against 11.13 mm. for the 

 check series. 



The trifling discrepancies in measurements, therefore, as well as 

 sculpture, enable us to say that the amount of increased variation 

 noted in the Florida-grown material is practically nil. It is not at all 

 unreasonable to believe that if an equally large number of Bahama 

 shells had been subjected to analysis parallel results might have been 

 obtained. 



Second Generation of Florida-grown Cerion viaregis. 



Of the second generation of Florida-grown Cerion viaregis, we have 

 now had 208 specimens from three different colonies. Table 14 gives 

 the measurable data presented by these and makes a comparison with 

 the check series from Andros Island, Bahamas. 



This discloses that the second generation of Florida-grown material 

 of Cerion viaregis is also slightly more variable than the check series 

 of Bahama material, for here we find that the greatest number of 

 whorls is 11.3 mm., while in the check series it is 11 mm. The altitude 

 measurement is 28.1 mm. against 27 mm. of the check series, while 

 the average greater diameter is a little less than that of the check 

 series, namely, 12.3 mm. against 12.7 mm. The least number of 

 whorls observed in any of the members of the second generation of 

 Florida-grown Cerion viaregis is 8.4 nam., while in the check series the 

 least observed was 9.1 mm. The least altitude of the Florida-grown 

 specimens is 17.3 mm. against 19 mm. of the check series, and the 

 least diameter is 9.3 mm. against 9 mm. of the check series. 



Table 15 shows that in the number of whorls the second Florida- 

 growTi generation presents only a negligible increase over the Bahaman 

 check series and the first Florida generation ; it likewise shows an aver- 

 age altitude measurement a little higher than the other two, but an 

 average diameter measurement halfway between the check series and 



