238 
Holothuria Jloridana and Holothuria atra 
I. INTRODUCTION. 
A. History of the Subject. Conclusions announced in this Paper. 
Pourtales, 1851, p. 12, described the Holothurid from the muddy flats of the 
Florida Keys as Holothuria Jloridana. This was recognized as a valid species by 
Selenka, 1867, pp. 324-6, PI. 18, Figs. 47-50, but this author probably included 
part of H. atra Jager, 1833, pp. 22-3, PI. 3, Fig. 2, in his Jloridana. After inves- 
tigating a good number of specimens from Florida and the Pacific Ocean, Selenka 
notes differences in (1) size of calcareous ring, (2) number of ventral pedicels in old 
individuals, (3) size of end-discs, and (4) number and size of stone-canals, but he 
concludes that such differences, being only of relative size and not of form, give 
no ground for specific separation. 
Semper, 1868, pp. 88, 92, 278-9, made of Selenka's atra the variety amhoinensis 
and gave ihe Jloridana of Pourtales as a synonym of H. atra from Celebes described 
by Jager. Since then all authors have followed Semper in relegating H. Jloridana. 
to the synonymy of H. atra. 
Ludwig, 1874, p. 101, described H. niexicana from one small specimen (6 cm. 
long), without gonads, in the Hamburg Museum under the rather indefinite 
locality-label of " Mexico." Clark, 1901, p. 258, identified specimens from Porto 
Rico as H. meadcana Ludwig. I have 10 of Clark's specimens included in the series 
from which my statistics were taken and they are in all respects like the average 
H. Jloridana as determined in this paper. Herouard, 1902, p. 8, identified 2 
specimens from the Azores as H. mexicana, although in some doubt from the fact 
that the spicules had been dissolved. 
Clark, 1902, p. 530, places specimens from Clipperton Island under H. atra 
(Jager) but is " confident that no less than three distinct species are now included 
under that name." 
Theel, 1886, pp. 174-5, PI. 8, Fig. 7, described a single specimen from Simon's 
Bay, Africa, as H. africana, and at the end of his description said, " The species in 
question is possibly identical with Ludwig's Holothuria mexicana." In view of 
the facts established by my studies, I believe we must confirm Theel's suggestion 
in making H. africana and H. mexicana identical, and further that the species 
common from Florida to the Caribbean region is distinct from H. atra and there- 
fore, to designate it, the name H. Jloridana Pourtales should be re-established 
(Edwards, 1905). The small individual described by Ludwig is, without doubt, a 
young H. Jloridana, and so H. mexicana Ludwig = {H. africana Theel) becomes a 
synonym of H. Jloridana Pourtales. 
The validity of Semper's variety amhoinensis was questioned by Ludwig, 1883, 
and denied by Lamport, 1885, and Sluiter, 1902. The last author examined a 
series of 21 specimens from 12 localities, and found all the intermediate stages 
