212 Charles Lincoln Edwards 



Holothuria floridana is found in large numbers in the shallow 

 bays and sounds on either the white coralline sand, or more generally 

 where the bottom is covered with green and brown vegetation. These 

 holothurians, sometimes uniformly seal-brown in color, but more 

 frequently particolored in varying mixtures of browns, creams, and 

 grays, are well protected both by their coloration, and by the habit 

 of covering themselves more or less completely with pieces of plants, 

 shells and sand held fast by the suckers of the pedicels. 



This species breeds during July and August, albeit some indi- 

 viduals may be found with mature gonads both before and after this 

 season. A number of attempts to artificially fertilize the eggs 

 failed. The live-box method employed by Selenka, 1876, was very 

 successful. About one hundred of the holothurids were collected 

 within an hour or two, and placed in a large box, the cracks of which 

 had been covered Avith cheese-cloth. The box was anchored to the 

 bottom in a shallow bay where at low tide the sea-water barely covered 

 it. In from four to ten hours eggs and sperms were extruded. The 

 oosperms, heavier than water, sank to the bottom and were gathered 

 through a rubber tube into shallow glass dishes. Pour lots of oosperms 

 were obtained in the summer of 1888, but in two succeeding Bahaman 

 expeditions I have not been able to secure the embryos. 



Holothuria floridana does not develop a free Auricularia larva, 

 but the embryonic stages are passed within the vitelline membrane 

 during the first five days after fertilization of the egg. On the sixth 

 day the embryo hatches as a larva with five primary tentacles, four 

 developed and one as a bud, and also with one posterior pedicel. 



In ray study of the order of development of the tentacles, pedicels 

 and papillae, embryos of each stage were reconstructed by plotting 

 the serial sections on paper. In this manner appendages were found 

 that could not be seen from a surface view of the whole embryo, and 

 the exact origin of each appendage from one side, or the other, of 

 a given radial canal, was determined. The interpretation of the 

 origin of an appendage based upon a surface view is sometimes mis- 

 leading, for the ambulacral canal may grow around in the body-wall, 

 pass over the radial canal and thus the appendage will emerge from 

 the skin upon the opposite side from which it leaves the radial canal. 



