148 



REPORTS ON INVESriGATlONS AND PROJECTS. 



RESULTS OF PLANUIvA CULTURES MADE IN I9IO. 



In 19 10, 203 planulae attached themselves, in culture-jars, to 21 terra-cotta 

 disks (tiles). Of these 21 tiles, 13, bearing a total of 160 polyps, were 

 placed in a floating live-car moored off the northwest face of Loggerhead 

 Key; while 8, bearing a total of 43 polyps, were planted on stakes driven 

 into the sea-bottom off the northwest face of the Fort Jefferson moat-wall. 

 In order to identify colonies that might develop from the planulae settled in 

 the aquarium from colonies that might develop from adventitious planulae 

 after the tiles were planted in the ocean, a diagram was carefully made of 

 each tile, showing the precise position of each attached planula. The neces- 

 sity of this foresight was amply demonstrated. By 191 1 at least 28 colonies, 

 representing 3 species, had developed from the cultures of 1910. 



PLANULA CULTURES PLACED IN THE FLOATING LIVE-CAR. 



An account of the initiation of this experiment with its history to Novem- 

 ber 1910 is given in last year's report.* It is stated in a footnote that this 

 car was sunk just before the hurricane of October 17, 1910, and that it was 

 subsequently refloated. John Mills, the head mechanic of the laboratory, 

 furnished notes on the condition of the cultures after the car was refloated, 

 but they could not be included in last year's report. The following table 

 presents the results of this experiment: 



Record of tiles ('laced in live-car anchored off Loggerhead Key. 



Culture number aud 

 name of parent. 



No. of plan- 

 ulae attach- 

 ed in May 

 and June 

 1910. 



Report of John Mills 

 Nov. 15, 1910. 



Report of Dr. Mayer, 

 Jan. 10, 191 1. 



No. of colo- 

 nies June 



1911. 



No.of plan- 

 ulae repre- 

 sented by 

 colonies. 



I. Favia fragura I*. 



4. Porites clavaria 1 . 

 6. Favia fragum I . . . 

 8. Favia fragum III. 



22. Porites astreoides 

 I. 



24. Porites astreoides 



II. 



25. Porites astreoides 



II. 



39. Porites astreoides 

 II. 



4 specimens ; diam 

 4.7 mm. 



3 specimens; diam. 

 largest 9.5 mm. ; in- 

 termediate 9 mm.; 

 smallest 8 mm. 



4 specimens; 2 diam. 

 4.7 mm.; 2 diam. 

 6.25 mm. 



I specimen ; diam. 



3 ram. 

 7 specimens; 5 diam. 



3 mm.; 2 diam. 



4.7 mm. 

 12 specimens; 7 diam 



3 mm.; 3 diam. 4.7. 



mm; 2 diam. 6mm. 

 4 specimens ; diam. 



3 ni m . 



3 specimens; diam. 

 largest 7 mm.; in- 

 termediate 6mm.; 

 smallest 5 mm. 



46 



* The Roman numerals refer to the parent specimen. Cultures Nos. 8 and 24 are illustrated by plate 4, 

 figs. I and 2. 



The measurements of John Mills were expressed in fractions of an inch 

 and were computed to millimeters. Some colonies escaped the notice of 

 both Mills and Dr. Mayer, because of trying to make observations under 

 water without removing the tiles from their places of attachment, the small 

 size of the colonies, or concealment by sea-weed or other organisms. I re- 

 moved the tiles from the car and cleaned and examined them in shallow 

 vessels filled with water. In some instances the present colonies were prob- 

 ably formed by the fusion of several planulae, or by the fusion of colonies 



* Carnegie Institution of Washington, Year Book No. 9, 1910, pp. 142, 143, plate 4, figs, 

 c and D. 



