46 IOWA STUDIES IN NATURAL HISTORY 
and found it to be hollow, the cavity occupying its entire length; 
he assumed that this cavity contained the viscera. A remark- 
able feature of this individual was that it possessed only four 
rays and eight arms; this was recognized by d’Orbigny as a 
curious anomaly. 
After d’Orbigny’s death his entire museum was purchased 
by the Jardin des Plantes (Museum d’Histoire Naturelle), 
where his specimen of Holopus was examined by Sir Wyyville 
Thomson in 1867. 
Roemer in Bronn’s Lethaea Geognostica, 1856, p. 226 (fol- 
lowed by Bronn in his ‘‘Klassen und Ordnungen des Thier- 
Reichs,’’ published in: 1861) proposed a new family, Holopide, 
for the reception of Holopus. 
In 1862 Dujardin and Hupe, in their ‘‘ Histoire naturelle des 
Zoophytes Echinodermes,’’ stated that from the published de- 
scription and figures of Holopus they were strongly inclined to 
consider it as something quite different from an echinoderm, 
and suggested that it might be a barnacle; they retained for it 
the family name Holopidae. 
In 1871 Dr. J. E. Gray® published the following note from 
Mr. (later Sir) Rawson W. Rawson, C.B., the Governor of 
Barbados, together with a figure of a specimen of Holopus lack- 
ing the bivial arms: 
‘‘T have procured a specimen of a Pentacrinus from the north 
of the island of Barbados, dredged or, rather, picked up, in 
about 5 fathoms water. It is ink-black, a portion broken so as 
to show the interior of the contracted armlets and the penta- 
erinal formation of the mouth or entrance of the central canals. 
Do you know what it is? I am under the impression of having 
seen an engraving of such a zoophyte, but cannot find it.’’ 
Mr. Rawson added in regard to the local habitat of this form 
and of the species of Jsocrinus: 
‘‘T believe that they are all procured on the same bank, which, 
instead of five or six miles from the shore, as I was first in- 
formed, cannot be more than a mile, within the hundred fathom 
line.’’ 
Dr. Gray at once recognized the figure as representing a 
3 Ann. and Mag. Nat. Hist., ser. 4, VIII, pp. 394-396, with a figure. 
