252 
Holothuria floridana 
In 18 individuals of Table XII. 27 of tlie tentacles have ampullae with 
branches. Of these, with origin as given in the Table, 18 have 1, 4 have 2, 
3 have 3, and 2 have 7 branches. 
In 16, d\ right dorsal radius arises under the mesentery, slightly toward the 
left and then passes over to the right. In 63, d\ right dorsal radius arises to the 
right of the mesentery and then passes beneath the mesentery to the left. 
The ampullae of 7 are rather remarkable in having altogether 23 branches and 
in that 2 (cZl, right dorsal radius and rfl, left ventral radius) have each 7 
branches in the form of a tuft. The branches are found only in adults and so 
indicate one of the changes which may come with advancing age. 
d. Variation in Size of Tentacles. 
Variations from the normal size of the tentacle may be classed as small and 
medium. The number of small tentacles present in Holothiirids of my series are 
found to vary from 2 in 42, 60, 93, 95, 96 and 3 in 18, 108 to 5 in 33 and 6 in 7. 
In addition to the 6 in the last case there are 4 tentacles of medium size. A 
stump of a tentacle, lost by accident, is present in 1, 56 and 58 and 2 such 
stumps in 42. In most cases it is probable that small and medium sizes are 
stages in regeneration from the stumps of those lost by accident although, of 
course, it is possible that they are congenital variations in size. 
e. Development of Tentacles. 
The completed study of the development of the ambulacral appendages 
necessitates some minor changes from my preliminary report (1907). The first 
4 tentacles are found on the 4th day, when the embryo is still within the vitelline 
membrane. Represented in accord with Fig. A, PI. V. the 4 tentacles arise from 
the radial canals as follows: — dl, left dorsal; d\, right ventral; rl, mid-ventral 
and d\, left ventral. The 5th, l\, mid-ventral, buds on the 4th day and thus 
completes the primitive symmetry. The 6th, d2, right ventral, has developed by 
the 40th day. From the 40th to the 49th days appear the 7th, c?2, left ventral, 
the 8th, dl, right dorsal and the 9th and 10th, vl, of either right, or left, dorsal. 
If the 9th arises from the right, then the 10th comes from the left, dorsal, or vice 
versa. The 11th, r2, mid-ventral, bads on the 49th day. The 12th, 12, mid- 
ventral, appears on the 71st day, and the 13th, the last in my series raised from 
the embryo, is (Z2, left dorsal, and is developed by the 75th day. 
E. Pedicels and Papillae. 
It is often very difficult to differentiate papillae from pedicels both as regards 
their form and the presence, or absence, of calcareous end-plates (cf Ludwig, 
1889-92, pp. 100—110; Lampert, 1889, p. 821 and 1896, p. 53). The whole 
