A PRACTICAL METHOD OF SPONGE CULTURE. 569 
RATE OF GROWTH. 
(Plates Lxrx to LXXvI.) 
The rate of growth of cuttings is a matter of paramount practical impor- 
tance to the prospective sponge culturist, and it has been the subject of con- 
siderable discussion and difference of opinion. ‘The fishermen variously claim 
that on the natural beds sponges grow to a ‘‘marketable size,’’ presumably 6 
or 7 inches in diameter, in from six months to a year, basing their statements 
on the fact that grounds supposedly denuded one year are found to bear salable 
sponges the next. They fail to consider the certainty that they have over- 
looked a number of large specimens and numerous small ones already well on 
their way to merchantable size. Smith, in his paper, ‘““The Florida Com- 
mercial Sponges,” basing his statement upon the reports of others, says that 
the claims of the spongers are borne out by experiments, and that ‘“‘in as short 
a time as one year, under favorable conditions, the cuttings will attain a mar- 
ketable size, and certainly within sixteen or eighteen months the harvesting of 
relatively large sponges may be depended on.”’ To substantiate the statement 
he furnishes a photograph, a careful inspection of which creates the impression 
that the photographer has somewhat assisted nature in establishing the apparent 
rate of growth. I have reason to believe that both Dr. Harris, the grower 
of the sponges in question, and Dr. Smith were deceived as to both the age 
and the origin of the larger specimen, and that it came from a mangrove root 
and not from a wire, as supposed. As photographed it is about 514 inches in 
diameter and is said to be not over eight months old, but I have seen a number 
of other sponges planted at the same time and place and under the same con- 
ditions which had attained a size of not over 4 inches when between three and 
’ five years old. They were all planted under unfavorable conditions, and the best 
result that I have been able to attain in the same locality and under better 
conditions of growth was an equal diameter in about two years from cuttings 
between 2 and 2% inches cube. 
The experiments by Fogarty at Key West about 1880 have not been accu- 
rately or definitely reported, but it is said that cuttings about 214 inches in 
diameter in some cases increased from four to six times in bulk within a period of 
six months. ‘This is more in accord with my own experience, though, as will be 
shown later, the relative increase in volume is greater with small cuttings than 
with larger ones: 
The results obtained by Buccich are also out of accord with the popular 
view of the rate of growth of sponges under natural conditions, although the 
reports of his work are lacking in definiteness. His cuttings, about 1 inch cube, 
increased to two or three times their original bulk in one year and did not reach 
full marketable size, the exact dimensions not being stated, until the lapse of 
seven years, a much slower rate of growth than in Florida. 
