1273 



Menzel, R. Winston. 1964. 



Checklist of the marine fauna and flora of the St. George's Sound area. Fla. 

 State Univ., Oceanogr. Inst., Tallahassee, Contrib. 61, 134 p. 



Mereenaria campechiensis is included, but not M. mereenaria. Representative 

 area is sand bars, grass flats, shell, and mud areas. Substrate is sand (mud). 

 Present throughout the year. Salinity range 25 to 37°/oo. Abundance: common. 

 - J.L.M. 



1274 



Menzel, R. W. 1964. 



Observations of quahog clams and their hybrids. Am. Zool. 4(3): 292. 



Northern quahog, Mereenaria mereenaria, from Conn., N.Y., Del., Va. , N.C., 

 S.C., and Fla. were crossed with southern quahog, M. campechiensis, from N.C. 

 and 3 localities in "la. Various backcrosses were made, as well as an F2 of 

 the F]_ of M. campechiensis Fla. female x M. mereenaria Conn. male. Meiotic 

 and mitotic chromosomes have been studied. - J.L.M. 



1275 



Menzel, R. Winston. 1964. 



Seasonal growth of northern and southern quahogs , Mereenaria mereenaria and 

 M. campechiensis , and their hybrids in Florida. Proc. Natl. Shellf. Assn. 

 53: 111-119. 



Growth of northern quahog, Mereenaria mereenaria, southern quahog, M. 

 campechiensis , and their reciprocal hybrids were measured monthly for 19 

 months in Alligator Harbor, Florida. Fastest growth for the four groups 

 occurred in spring and fall. Northern quahog had the least overall growth 

 (8 mm clams growing to 41 mm average length) and showed least growth during 

 the hottest period of the year. Southern quahog had the best overall growth 

 (growing from 8 mm to 57 mm in average length) and grew least in the coldest 

 period. Growth of hybrids was intermediate between that of parents but 

 closer to the southern than to the northern parent, 8 mm clams growing to 

 average lengths of 52 and 55 mm in 19 months. Growth rate of hybrids was 

 better than that of either parent in late spring and early fall. - modified 

 author's abstract - D.L. 



1276 



Menzel, R. W. 1966. 



Studies of the F, and F 2 hybrids of the northern and southern quahog clams. 

 Assoc. SE Biol. Bull. 13(2): 41 (abstract). 



During the first half of five years' observations of northern and southern 

 parents (Mereenaria mereenaria and M. campechiensis) and reciprocal hybrids, 

 the southern species grew fastest, the northern slowest, and the hybrids 

 intermediate but close to the southern parent. During the latter half hy- 

 brids surpassed both parents. The F-^ hybrid of the cross, female M. 

 campechiensis x male M. mereenaria , grew larger than those of the reciprocal 

 cross, and their F 2 s were the most successful. The F 2 of the reciprocal 

 cross all died within one month. A limited number of F 2 s from reciprocal 

 crosses between F-^s and the first mentioned F 2 are still growing. Although 

 still too small for final characterization, they so far resemble the south- 

 ern parent in shell morphology. - J.L.M. 



356 



