. The Canadian field-naturalist. . Figure 1. Three views of a five-banded Cepaea nemoralis shell. Bands are numbered. separate bands is designated as 1 2 3 4 5. A missing band is designated by '0.' A complete fusion of two bands is designated by a round bracket and an incom- plete fusion by square brackets around the bands involved. Presence or absence of any combination of five bands along with fusion of any two or more bands provides a large number of possible phenotypes in any colony. In the first colony (A) which was located near the western city limits on grassy plots, Judd (1953) found t
. The Canadian field-naturalist. . Figure 1. Three views of a five-banded Cepaea nemoralis shell. Bands are numbered. separate bands is designated as 1 2 3 4 5. A missing band is designated by '0.' A complete fusion of two bands is designated by a round bracket and an incom- plete fusion by square brackets around the bands involved. Presence or absence of any combination of five bands along with fusion of any two or more bands provides a large number of possible phenotypes in any colony. In the first colony (A) which was located near the western city limits on grassy plots, Judd (1953) found that over 90% of the shells expressed all five, bands. Of these 35% were 12 3 4 5,43% were 1 2 3 [4 5], and 10% were 1 2 3 (4 5). All other 27 recognized patterns were present in much lower frequencies. In a sample size of 1000, 13 of these patterns were repre- sented by single individuals and 5 by only two individ- uals. For others the frequencies were less than 2% each. Thus characteristically this population was pre- dominantly 12 3 4 5 type with some fusion of bands 4 and 5. Furthermore, there were no003--(0 03 with presence or absence of bands 4 and/ or 5) individuals in this colony. In a second colony (B) which was located in a well-maintained garden within the city limit 5 km NE of the first colony, Judd (1955) noted that the frequencies of banding patterns were signifi- cantly different from the first colony. About. 25% of the snails were 0 0 (absence of bands 1 and 2) as compared to 1 /1000 in the first colony. The fusion of bands 1 and 2 was pronounced in the second colony (41%,) as compared to the first colony (2%). Further- more, the band pattern 0 0 3 00 was present only in the second colony. This study was undertaken to see if more colonies of C. nemoralis have developed since 1952 and how they compare with the findings of Judd (1953, 1955) in this area. Materials and Methods During the summer of 1979, 10 additional colonies of C. nemoralis were located within the
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