572 
BULLETIN OF THE BUREAU OF FISHERIES 
the Beaufort (N. C.,) scallops very close to those of Cold Spring Harbor, N. Y., 
and noticeably different from those of Tampa, Fla., but admits the possibility of 
intergrades. The modal number of shell rays or ribs is given as follows: Cold Spring 
Harbor, 17 ; Beaufort, 17 ; and Tampa, 20. It is not clear from the context how the 
number for Beaufort was obtained, although abundant data for the other points are 
given. I made a count of rays on Beaufort shells and found 18 most prevalent, but 
with 17 nearly as numerous. The extremes in this count, which included 150 right 
valves and 46 left valves, were 16 and 20. (See Table 2.) The number was deter- 
mined by counting the inner grooves much as was done by Davenport, except that 
two half grooves were not taken to equal one full groove. Jacot (1921), presumably 
counting the outer ribs instead of the inner grooves, found two subspecies, one com- 
monly with 19 ribs (18-20) the other with 20 (19-22). 
Table 2. — Counts of rays or ribs on scallop shells from Beaufort and vicinity 
16 rays 
17 rays 
18 rays 
19 rays 
10 
52 
68 
16 
4 
13 
21 
9 
14 
65 
89 
25 
Like Davenport, I hesitate to pass on the question of species. I accept Dali’s 
decision in favor of one species for our Atlantic coast and consider that the available 
morphological evidence is strongly in favor of the view that the bay scallops, at least 
of the important commercial centers (North Carolina, New York, Virginia, and Mas- 
sachusetts) are specifically the same. In Bulletin No. 37 Dali (1889) employed the name 
Peden irradians Lamarck. In the “Tertiary Fauna of Florida” (Dali, 1898), on the 
ground of integradation with the Jamaican scallop which Linnseus described as 
Ostrea gibba, he employs the name Peden gibbus Lirme with irradians as a subspecies. 
Kellogg, Drew, and Belding use P. irradians. In correspondence, Dr. Paul Bartsch 
expressed himself in favor of that name, in the belief that our scallop is distinct from 
that of Jamaica; and Dr. H. A. Pilsbry favors it if the binomial is used. The name 
Peden irradians Lamarck is here employed. 
Although on morphological evidence the Beaufort and Massachusetts scallops 
are held to belong to one species, it is perhaps worthy of note in this connection that 
in one important biological aspect — spawning — the Beaufort scallops differ markedly 
from those of northern waters. The Beaufort scallops spawn principally in the fall 
when water temperature is falling; the others, according to Risser (1901) and Belding 
(1910), in the spring or early summer when the temperature is rising. 
HABITAT AND DISTRIBUTION 
According to Dali (1889) the range of Peden irradians is from Nova Scotia to 
Tampa, Fla. Later (1898) he concluded that West Indian scallops were specifically 
the same as those of our Atlantic coast and that the species extended to Brazil. 
Kellogg (1910) reports it from the vicinity of the Chandeleur Islands in the Gulf of 
Mexico, and gives the range as Cape Cod to Texas. Belding (1910) states that it 
occurs from Massachusetts Bay to the Gulf of Mexico, but adds that a few are reported 
to be found in some of the warm bays of the Maine coast. Ingersoll (1887) found it 
rare or local “north of that great dividing point” — Cape Cod. In important com- 
mercial abundance it occurs so far north as Cape Cod and at least as far south as 
