632 U. S. BUREAU OF FISHERIES 
duced spawnings may be considered to have been unsuccessful, except on three 
occasions. On two of these development proceeded only to few cell stages. 
On the third attempt. embryos developed well and large numbers of shelled 
larve were obtained. These grew beyond the latest stage studied by Belding, 
but not beyond the straight-hinge stage. They were measured, sketched, and 
supposedly preserved, but, like the extensive but incomplete embryological 
material, came through in very poor condition. It was thought that these and 
the prodissoconech shell on small postlarve would make the recognition of larval 
scallops a reasonably simple matter. However, very few straight-hinge larve 
like these have been found, and no larger forms that could be surely con- 
nected with them. Until recently no postlarve have been found that showed 
the prodissoconch shell at all clearly. Little progress, therefore, has been made 
in this direction. However, perhaps it is worthy of note that the larval stage 
is thought to be of brief duration, for the egg is decidedly larger than that of 
Ostrea virginica and the larva attains a much smaller size, only (about 0.18 
millimeters in extreme length). 
Growth rate and age are very important, from a practical standpoint, and are 
not so elusive aS spawning and some other problems that confront the investi- 
gator. They have received special attention. Data compared have been en- 
tirely from Pivers Island scallops. At first, collections of 50 were made once 
a week. Later this was changed to 100 twice a month—a more satisfactory 
arrangement. Data thus secured are regarded as quite satisfactory, except 
at the two ends of the series of collections. 
In January, 1926, at my recommendation, the scallop season was opened. 
Contrary to my recommendation, no exemption was made of flats at Pivers 
Island (the laboratory) and in the last three days of the season they were 
denuded almost completely of scallops, thus ruining all chances of obtaining 
satisfactory disappearance data. Data for small stages also were deficient. 
For quite a while no small scallops were seen; thereafter, until recently, only 
seattering numbers were found (except that a moderate size was attained in 
the spring of 1926). Yet the crop this year is comparable with that of last year. 
Various methods of collecting material were tried. Fine nets were dragged 
through the grass, grass was collected and rinsed in water, and the water was 
screened—no scallops. After long searching, some were found attached to 
grass. Next, spreading and drying the grass on newspapers was tried with 
considerable success, but still with uncertain results. This fall, in desperation 
it was determined to rake up much larger quantities of “ grass,’ a washtub full 
being chosen. Although this represents a greater amount of labor in the 
collecting than would be imagined, and some day’s work in subsequent study, 
it has been adhered to with increasingly satisfactory results. I feel that if 
the Pivers Island flats do not fail me, satisfactory growth (and death) data 
may be expected by another year, and with them a good understanding of the 
spawning season. Of course, unless there is a great deal of improvement on 
the depleted areas, the data inevitably will suffer from extreme localization. 
Tagging experiments to obtain information as.to growth, longevity, and spawn- 
ing time are being tried on a small scale. 
The growth data taken for mid-month periods are presented in a series of 
graphs (fig. 18), which, with sufficient clearness, show two year Classes and 
indicate growth to market size in not much over a year. A normal fall growing 
period is indicated by the special graph for 1925 and by data for 1926. 
Doctor Giteert. What is the extreme age of the scallop? 
Mr. Gursetxt. I don’t know. Belding’s idea was about 2 years. 
He found a few spawning a second time. He found very plain year 
marks on the shell. Presumably because in the South there is winter 
growth, I didn’t find anything that I could be sure of in the way 
of rings at this stage. Sometimes there would be three or four 
rings on a small scallop, one just as plain as the other. For a period 
of about three months (September to November) there is practically 
no growth. That is based on averages. This was also very plain by 
inspection of new growth in the fall. This year it was somewhat the 
same, but not so definite. What the explanation for the lack of 
growth in the fall is, I have no idea. It doesn’t seem to have any- 
thing to do with spawning or anything else. 
