144 



REPORTS ON INVEISTIGATIONS AND PROJECTS. 



The parentage of four of the Porites astreoides planulse was not definitely 

 known; this was also the case with the one successful culture of Agaricia 

 crassa, but the mortality of the young of this species is known to be high. 



Definite conclusions on the vitality of the planulse of different species and 

 on the planulae of different specimens of the same species perhaps can not be 

 drawn from these data, but they are suggestive and the suggestions are here 

 given. There is variation in the vitality of planulse both between different 

 species and between the planulae of different colonies belonging to the same 

 species. The planulae of Porites astreoides are the hardiest ; those of speci- 

 men II of this species were hardier than those of specimen I, while none of 

 those of specimen III survived. Comparing species, Favia fragum fur- 

 nished the next hardiest planulae, two of four specimens yielding successful 

 cultures ; while from only one of four colonies of Porites clavaria were at- 

 tached planulae obtained. Agaricia crassa ranks about with Porites clavaria. 

 It is important to obtain as complete data as possible on the vitality of plan- 

 ulae and the duration of the free-swimming larval stage, as on them depend 

 the ability of planulae to be distributed by ocean currents. 



Additional information was obtained on the duration of the free-swim- 

 ming larval stage, but as a complete presentation of the data would necessi- 

 tate a long table only a summary is given. 



Duration of the Free-swimming Larval Stage in Experiments of 1910. 



Most of the planulae in culture 25, the one in which most larvas became 

 attached, attached themselves on the nineteenth day, or they were free 18 days. 

 The planulae in 41 cultures were extruded between May 18 and May 24. 

 The water on some of them was first changed on May 28, on the 29th it was 

 changed on all, and subsequently it was changed every day. As previous to 

 May 28 only one planula had become attached, it is thought that the stale 

 water may have prolonged the free-swimming stage. 



The data for 1910 show longer duration of the free-swimming stage than 

 did those for 1908 and 1909. Larvae that can swim or float in the water 

 from two to three weeks can be transported enormous distances by ocean cur- 

 rents. Madreporarian planulae have frequently been obtained in the plank- 

 ton tows off the Tortugas, clearly showing that these larvae in that region 

 come within the influence of the ocean currents. 



Report of Prof. John B. Watson on the Work on Bird Key. 



The past season was one very unfavorable for carrying out work upon dis- 

 tant orientation. The heavy storms in the Gulf region were the chief causes 

 of the difficulties. 



In 1907 the work upon the homing sense of the terns was incidental, 

 whereas in the season just passed it was the principal feature. For this 

 reason it was desirable to send out large numbers of birds. The shipping 

 technique was very faulty until toward the very last. Twelve to fourteen 



