DISTRIBUTION OF HOLOTHURIANS. 217 
body ends in a long, tail-like prolongation; C. arenata 
Stimpson has fifteen four-pronged tentacles; it is com- 
monly thrown up on the beaches 
of Massachusetts Bay. A deep- 
water form, a member of the 
abyssal fauna, is Molpadia tur- 
gida Verrill, which we have 
dredged in over one hundred 
fathoms in the Gulf of Maine, 
and which ranges southward to _‘#ig.154.— Hooks and plates of 
Florida. It has a head-end like “#4 @ardti—After Vernil. 
the neck of a bottle, and the end of the body suddenly con- 
tracts into a tail, with a very small anus. There are fifteen 
tentacles. 
Order 2. Pedata, or Holothurians with feet. The mem- 
bers of the first family (Dendrochirote) have tree-like, 
branching tentacles, retractor muscles, without Cuvierian 
organs. It is represented by Thyone and Pentacta, while 
here belong also Lophothuria Fabricit Diben and Koren, 
Psolus phantapus and P, sguamatus, in which the body is 
armed with heavy calcareous plates, and the feet are confined 
to a ventral creeping disk. 
In the highest family, Aspidochirote, there are tentacular 
ampulie ; the left respiratory tree is bound to the body- 
walls, and there is a single ovary, while Cuvierian organs 
are present. Holothuria is the type of the group. H. edulis 
Lesson, of the Moluccas and Australia, and A. tremula 
forms, when dried, the trepang sold in Chinese markets. 
Our H. floridana has been dried and exported to China as 
an article of food. 
In their geographical distribution the Apoda are mostly 
boreal and arctic. Of the Pedata, the Dendrochirote are 
mostly northern or arctic, while the highest group, Aspi- 
dochirote, are mainly tropical. Certain genera (Holothuria, 
Thyone, Psolus, Pentacta, Chirodota, and Synapta) are almost 
cosmopolitan. 
A few forms attain a great depth, and certain abyssal 
forms are often highly colored. One species, Synapta 
