29(3 
Holothuria floridana and Holothuria atra 
The remaining tentacles, so far as my series from the embryo extends, arise in 
the following order. — 5th, l\, mid-ventral; 6th, d2, right ventral; 7th, rf2, left 
ventral ; 8th, d\, right dorsal ; 9th and 10th, either vl of right or left dorsal ; 11th, 
?'2, mid-ventral ; 12th, Z2, mid-ventral, and 13th, rf2, left dorsal. 
The tentacle ampullae have branches in 15 of the specimens. 
Development of pedicels and papillae. — The 1st pedicel buds from the posterior 
end of tlie mid-ventral radial canal in the 4th day. The next 3 arise from and 
always to the left of the mid-ventral radial canal and not until the 40th day 
does a pedicel appear to the right fiom this radial canal. The 1st pair of papillae 
appears on the 24th day ventrad from the anterior ends of the dorsal radial canals 
and will become warts. On the 30th day the 1st pair of pedicels appears from 
the lateral ventral radial canals. Gradually the number increases until the 7.5th 
day when there are 30 developed and 68 buds, mostly arranged in bilateral rows. 
The smallest of the fully-developed young has 77 developed pedicels and papillae 
in rows but later on the inter-radial regions of the adult show evenly distributed 
appendages. 
A7ial papillae. — In 5 groups in a majority of the specimens. 
Spicules. — The rosettes are characteristic of the young and the perforated 
plates of the adult. The average of the standard deviations in number of holes in 
the dorsal and ventral rosettes with holes is r5. 
Perforated jjlates. — Averages of the standard deviations of each character in 
bivium and trivium have the following order : — ■ 
a. Developmental stages ; — number of holes (TO), width (2'8) and length (3 0). 
b. Developed plates ; — Width (2'6), length (31) and number of holes (3'4). 
Polian vesicles. — The standard deviation of the number of vesicles and branches 
is greater than that of the greatest length in the adult, and the reverse is true in 
the young. The variability in the number of vesicles and branches in the adult 
is 6 times that of the young and in the greatest length, twice that of the young. 
Stone-canals. — The standard deviations of the various characters increase in 
the following order: — Adult, average length (r7); greatest length (4-1); number, 
left (irS), right (15"9), total (24-7): Young, average length (1"4), greatest length 
(2-2), number, left (2-5), right (4-0), total (6-0). 
D. Additional Characters of H. atra. 
Dimensions. — The young average 8 cm. in length, 2 cm. diameter and 20 cm.^ 
volume. 
The adult average 16 cm. in length, 5 cm. in diameter and 170 cm.^ in volume. 
The greatest length is 33 cm. The greatest diameter 8 cm. and the greatest 
volume 538 cm.^ 
