NATURAL HISTORY OF THE BAY SCALLOP 
573 
Bogue Sound, N. C. A small commercial catch is recorded for Florida in 1928. Areas 
famous for the abundance (past or present) of scallops are : The south shore of Cape 
Cod and Buzzards Bay, Mass.; Greenwich Bay, R. I.; Long Island Sound, particu- 
larly sections of the Connecticut shore (unproductive since an early date); Peconic 
Bay, Long Island, N. Y. ; and Bogue Sound, Core Sound, and Beaufort Harbor in 
North Carolina. In suitable coastal areas between Long Island and North Carolina 
it occurs, or has occurred, sometimes in commercial numbers. Of recent years im- 
portant catches have been taken near Chincoteague, Ya. 
The range in depth is from that of flats with only a foot or so of water over them 
at ordinary low water (bare at extreme low water) to as much as 60 feet (Belding, 
1910). In North Carolina, where the sounds are very shallow, comparatively few 
scallops are found at a depth of much more than 6 feet. 
As its name implies, the bay scallop is principally an inhabitant of inclosed 
waters — bays, harbors, estuaries, and sounds. These may be either of ocean saltness 
or decidedly brackish. Belding (1910) states that the density (temperature not 
given) may be as little as 1.010. In North Carolina scallops occur in commercial 
abundance in water ordinarily ranging in salinity from about 20 parts per mille 
(possibly decidedly less for brief periods) to 38 parts per mille. There may be a 
strong tide, a moderate tide, or almost none. Ordinarily scallops occur amid a 
growth of eelgrass (Zostera) or other vegetation. This plant growth may be long 
and heavy or short and sparse. The type of bottom varies from soft mud to hard 
sand (but not shifting sand). 
ORGANIZATION AND MODE OF LIFE 
SHELL 
The general outline and appearance of the shell of an adult scallop are shown in 
accompanying photographic illustrations. (Figs. 1 and 2.) In addition, Figure 5a 
illustrates the cross sectional shape of the ribs and Figure 5b that of the shell, 
through center of umbo, fossette, and central rib. The umbos are straight (nonspiral) 
and approximate and directed at right angles to the hinge, near the center of which 
they are located. The central position of umbos relative to the anterior and pos- 
terior portions lias, in an allied species, led Dakin (1909) to term the shell equilateral, 
although there are small posterio-anterior differences which strictly make it inequi- 
lateral. The deeper cupping of the lower right valve makes the shell inequi valve, a 
condition found in comparative!} 7 few lamellibranchs and doubtless an adaption to a 
lateral position in life. The deep byssal notch in the right valve is anterior, and the 
fossette or cartilage box points somewhat anteriorly. The adductor muscle impres- 
sion is posterior but very faint, as is also the pallia! line (without sinus). The shapes 
of the auricular regions or “ears” are well shown in the photographs. (Figs. 1 and 
2.) The posterior auricular margin is slightly obtuse, the anterior reflected. 
The long, thin external ligament (the ligament proper) extends the length of the 
hinge either side of the umbos (the type termed by Dali (1895) amphiaetic) and holds 
the valves together along the hinge line. The cartilage (or so-called internal ligament, 
the resilium of Dali), roughly pyramidal in shape and well supported in its fossette 
or box, adds considerably to the strength of the hinge but has the primary function 
of tending, like a compressed spring, to open the shell. Cooke (1895) states that the 
ligament is inelastic and insoluble in caustic potash, the cartilage very elastic and 
soluble in caustic potash. The cartilage, in thin pieces, is a clear red amber and of 
