Development of Holothiiria Floridana Pourtales 225 



of the adult Holothuria floridana (Edwards, 1908). However, most 

 of the dorsal appendages will become pedicels since in the adult 

 only about twenty per cent are papillae. 



On the thirtieth day a pedicel buds ventrad from the right and 

 left ventral radial canals. By the thirty-third day these lateral 

 pedicels have developed (PL II, Fig. 8, rvp, Ivp), and by the fortieth 

 day two additional buds have appeared below each lateral ventral 

 radial canal (PI. II, Fig. 10). On the forty-second day one bud 

 arises dorsad from each lateral ventral radial canal. From this 

 time on the number of appendages increases with comparative rapid- 

 ity and an approximate bilateral symmetry is established (PL III, 

 Figs. 11-14). For the details of distribution I refer to Table II. 



In one specimen of the fortieth day, nine developed appendages 

 and sixteen buds have appeared ; by the forty-fifth day, twenty-seven 

 developed and twenty-three buds ; by the fifty-fifth day, thirty-six 

 developed and twenty-six buds and by the seventy-fifth day a total 

 of ninety-eight (Pis. II-III, Figs. 10-14). The largest number of 

 developed appendages, thirty-six, is found in a fifty-five day holo- 

 thurid, while among the smallest specimens of my collection not raised 

 from the embryo, the least number of developed appendages shown 

 is seventy-seven. If studied in sections, these small individuals 

 would doubtless be found to have buds and show a considerable in- 

 crease in the total number of appendages. Since the seventy-five 

 day young presents a total of ninety-eight appendages, developed 

 and buds, it may be assumed that the later stages in my holothurids 

 from the embiyo, connect this series with the adult and that ap- 

 pendages will continue to bud from each radial canal in a manner 

 similar to that described up to the eighty-seventh day. 



There is a tendency, perfectly demonstrated in part of the 

 specimens, for one or another radial canal to terminate posteriorly 

 in the bud of an appendage, either lying in the radius, or turned 

 slightly dorsally or ventrally. As the radial canal grows on poste- 

 riorly, such a terminal appendage becomes either ventral, or dorsal, 

 to the canal in position. At first the ordinary larval appendages 

 gTOw off to the sides of the radial canals and, hence, the lines of 

 the radii are bare. This is especially true of the mid-ventral radius. 



