Growth of Nassarius obsoletus occurs principally during the summer 

 months. The winter is passed in a state of quiescence below mean low 

 water. Zero- and one-year classes are readily distinguished, but 

 after the third summer the various age groups can no longer be 

 identified by the length-frequency method. The longevity of Nassarius 

 obsoletus cannot be directly determined, but some individuals probably 

 live to at least five years. A growth of 1.3 to 1 .4 mm per month was 

 estimated during the first two summers in a New England population 

 found in Great Pond, Falmouth, Massachusetts. An increase in length 

 of 3 to 5 times that at the time of metamorphosis occurs during the 

 first summer's growth. (A. A.) 



Keywords: mud-snails, feeding habits, intertidal flats, Massachusetts 



V-D-7 



Davis, L.V., and I.E. Gray. 1966. Zonal and seasonal distribution of 



insects in North Carolina salt marshes. Ecological Monographs 36:275-295. 



The main purpose of this study was to describe the zonal and seasonal 

 distribution of the principal species of insects from the herbaceous 

 strata of the major types of salt marshes in Carteret County, North Carolina. 

 The responses of these insects to flood conditions, and their trophic 

 relationships, were also observed. 



The salt marshes of the study area are classified as follows: 

 (1) the Spartina alterniflora association, which occurs on substratum 

 inundated at each high tide; (2) the Spartina-Salicornia-Limonium 

 association, which occurs on substratum inundated at each high tide; 



(3) the Spartina-Salicornia-Limonium association, which occurs on slightly 

 hiqher ground, and forms a narrow zone just above S. alterniflora ; 



(4) the Juncus roemerianus association, which grows on flats inundated 

 by spring tides, and occurs just above Spartina-Salicornia-Limonium ; 



(5) the high marsh association, of which there are two principal 



facies, the first dominated by Distichlis spicata and occurring principally 

 within or on the margin of Juncus marshes and at about the same elevation, 

 and the second dominated by Spartina patens and usually occurring on 

 sandy ground above the Spartina-Salicornia-Limonium zone, at a level 

 seldom reached by high tides . 



The insect assemblages of each type of marsh were sampled by sweeping 

 the vegetation. The period of most intense sampling was June, July, 

 and August, 1960, when sets of ten samples were obtained from twenty 

 stations, of which six were established in S. alterniflora , one in 

 Spartina-Salicornia-Limonium , four in Juncus , four in Distichlis , 

 and five in S. patens . Samples were also taken monthly from one or 

 more stands oT each type of marsh from September 1, 1959, to June 1, 1960. 



The ordinal composition of samples from stations included in the summer 

 sampling program was determined. Homoptera predominated at fourteen 



255 



