Report on the Bahama Cerions planted on the Florida Keys. 211 
The 20 specimens of the first generation from the north colony of 
Loggerhead Key, Tortugas (plate 2, top and bottom rows), are extremely 
interesting. They possess a greater number of whorls than the check 
series or parent generation (plate 2, middle row). The altitude is also 
greater, the average of the check series being 26.37 mm.; that of the 
present generation, 28.80 mm. The variation in this measurement is 
also much increased, ranging from 25 mm. to 34 mm., as against 24.5 
mm. to 28.5 mm. of the check series—. e., there is a range of 9 mm. 
in the present series against 4 mm. of the check series. This raises 
TaBLe 3.—First generation of the “White House Type’’ cerions from the 
north colony of Loggerhead Key, Tortugas, Florida. 
[Plate 2, top and bottom rows.] 
Measurement of shell, 
No. of in millimeters. 
No. 
whorls. | 
| Altitude. | Diameter. 
i 11.4 S10 )na | 12.3 
2 Uh i 29 12 
3 10.5 Suleye 13.6 
4 12 134 1223 
5 10.6 an 14.5 
6 ibs 33 28.1 i a Wega 
7 11.4 Bill ae 13 
8 11.9 Bul ve! 2 it 
9 11.6 30.2 12 
10 1s 28.1 12.3 
11 Tape 2708 11.8 
12 L9 28.2 1255 
13 TE Sit 26.5 12.8 
14 10.5 25 1 a Gas 
15 iit t 28 1 Lass 
16 10.9 2653 11 
i IF 11:2 laa 11.8 
18 10.4 26.5 12.8 
19 10.6 26 12 
Average..| 11.17| 28.80 | 12.28 
Greatest..| 12 \y) 4 14.5 
Least... .) 10.4 | 25 11 
*Altitude estimated; shell not quite adult. 
the variation in altitude 7 mm. above that observed in the first gen- 
eration born and grown upon Bahia Honda, Florida. The average 
diameter in the north colony drops below that of the check series, 
being only 12.28 mm., against 12.59 mm. The range of variation, 
however, is much greater—1. e., 11 mm. to 14.5 mm. against 12 mm. 
to 13.3 mm. of the check series; or 3.5 mm. against 1.3 mm. This 
variation exceeds even that of the Bahia Honda grown first generation, 
in which it was 2.3 mm. 
The shape, coloration, and sculpture have also undergone decided 
modification in some of the specimens. There is a pronounced tendency 
in the entire lot toward greater elongation. This tendency reached its 
