140 



REPORTS ON INVESTIGATIONS AND PROJECTS. 



The specimens on the piers show an increase in length and breadth of as 

 much as 64 and 79 per cent ; in height, 41 and 105 per cent. One specimen 

 that in 1908 had one nodule on its surface, in 1910 had seven stocks, each 

 subdivided ; thus within two years an incrusting base may develop a clump 

 of branches. The growth-rate varied greatly between the specimens in the 

 moat, seemingly those nearer the exits growing more rapidly than those 

 more distant. The increase in length in one instance reached 210 per cent; 

 in breadth, in the same specimen, 163 per cent; the maximum increase in 

 height was 207 per cent, while in the other more favorably situated colonies, 

 6y, 69, 74, 92, 155, and 168 respectively represent the percentage increase. 

 The branching is as rapid as the general growth ; a few nodules of one year 

 may be replaced in the succeeding year by stocks and clusters of branches, 

 rendering recognition of the colony in successive years impossible without 

 marking. Within three or four years a rather large colony may be produced. 



In 1910 the number of records for P. furcata was increased to 26. 



During the field season of 1910 additional colonies living on the reefs off 

 Loggerhead Key, on the piers of the Fort Jefferson dock, and in the moat 

 were measured and records were made. Specimens of corals fastened by 

 Portland cement in 1909 thrived, showing that this material can be used in 

 affixing corals for planting in desirable localities. Eighty-six specimens 

 were cemented to tiles, and after having been photographed and measured 

 were planted on iron stakes off the northwest outer face of the Fort Jeffer- 

 son moat wall in water ranging from 12 to 18 inches in depth at the lowest 

 tide. Ten other specimens were cemented to tiles and, after having been 

 sketched and measured, were planted in a live-car, intended to withstand 

 hurricanes, off Loggerhead Key. 



The number of records by species is as follows : 



Number of Growth Records by Species. 



These 203 records are distributed over 18 species, forms, or variations. 

 Less than 10 records for a species is of course valuable, but as so small a 

 number is not sufficient, an effort will be made to get at least 10 records for 

 each species. This is possible in most instances, for a colony may be divided 

 and each part, after attaching it with cement, can be used for growth experi- 

 ments. At present there are no serial observations or measurements on 9 

 species or forms known to live around the Tortugas, but, as material can be 

 obtained of 4 of these 9, the deficiency can be partially remedied during the 

 next season's field work. 



Young stages of about half the species have been obtained, permitting the 

 growth to be rather confidently followed from the end of the first year. 



