270 
Holothuria floridana 
The branching of vesicles and the formation of tufts and tufts with branched 
vesicles are due to the continued growth and multiplication of these organs along 
with the growth of the adult Holothurid, for 3G 7o of the adult have tufts and tufts 
with branched vesicles, while only 4 of the young have tufts and none have 
tufts with branched vesicles. Ludwig, 1889-92, p. 113, gives H. mexicana and 
H. africana among the species in which several vesicles spring from a common 
stalk. Because of the variation in size of both vesicles and branches, in order to 
simplify the matter, in making Table XXII. I have grouped vesicles and branches 
together. 
TABLE XXII. 
Polian Vesicles. 
Addlt; 73 Specimens 
Young ; 45 Specimens 
Number of 
Vesicles 
and Branches 
Greatest 
Length 
mm. 
Number 
of Vesicles 
and Branches 
Greatest 
Length 
mm. 
Mean 
Standard Deviation 
Coefficient of Variation . . . 
Range of Vai'iation 
12 -563 + 1-203 
15-774+ -893 
125-550 + 7-107 
1—92 
25-429+1-002 
12-058+ -687 
47 -427 ±2 -703 
8—73 
2 -667 ± -321 
2-494+ -177 
93-513+ -665 
0—16 
10-140+ -801 
6-822+ -506 
64-278 + 4-893 
2—29 
The mean number of Polian vesicles and branches is 13 with a range of 1 — 92, 
in the adult, and only 3 with a range of 0 — 16 in the young. Eighteen per cent, 
of the adult have only 1 vesicle while 74 "j^ of the young have 1, 12 have 2 and 
only 14°/^ have more than 2 vesicles. 
The mean greatest length increased from 10 mm. with a range of 2 mm. — ■ 
29 mm. in the young to 25 mm. with a range of 8 mm. — 73 mm. in the adult. 
These facts demonstrate that, as in the formation of branches and tufts noted 
above, the number of vesicles and branches and their length increase with the 
growth of the Holothurid. Lvidwig, 1889—92, p. 114, notes that most species 
have only 1 vesicle in the beginning, and that there are only 3 families in 
which these organs fail to increase in number. It is possible that most authors 
do not include the branches in the number of Polian vesicles given. Lampert, 
1885, p. 85, notes 2 branches on the Polian vesicles. Not counting the branches, 
from Table I. it is found that the mean number of vesicles in the adult is 11, the 
four largest numbers being 40, 41, 58 and 79. Lampert, 1885, p. 85, remarks 
that in H. mexicana the Polian vesicles are very inconstant and may be conceived 
of as in continuous multiplication. Ludwig, 1889-92, p. 115, gives the number 
of Polian vesicles in H. mexicana as 1 — 13. Theel, 1886, p. 175, in describing 
H. africana says: "The Polian vesicles are numerous, up to 12 or more, of 
unequal size and some of them carry small branches at their base." From my 
series, as given above, the range of variation is greatly increased. 
