60 IOWA STUDIES IN NATURAL HISTORY 
plane, closing the proximal end, and that this ring becomes at- 
tached by its lower border to the object upon which the larva 
rests. 
THE KNOWN SPECIMENS OF HOLOPUS RANGII 
1. Martinique (PI. I, figs. 1, 2). 
Caught by a fisherman and given to M. Sander Rang while 
still alive; by him presented to M. Alcide d’Orbigny, who de- 
seribed it in 1837. 
Figured by d’Orbigny in ‘‘Magasin de zoologie, Tieme annee, 
classe X, pl. 3, 1837.’’ 
Purchased by the Muséum d’Histoire Naturelle at Paris, and 
there examined by Sir Wyville Thomson in 1867. 
Type of Holopus rangu d’Orbigny, 1837, this species being 
the type of the genus Holopus. 
2. Barbados (PI. I, fig. 3). 
Found in 5 fathoms, but at first thought to have been brought 
up from ‘‘deep water.’’ 
Originally in the collection of Sir Rawson W. Rawson. 
Governor Rawson sent a sketch of it, with a short note, to 
Dr. J. E. Gray, both of which were published by the latter in 
1871. The specimen was not sent to Dr. Gray. 
During the visit of the ‘‘Hassler’’ to Barbados in December, 
1871, Governor Rawson loaned this specimen to Professor Louis 
Agassiz for the latter to describe and figure. His figures with 
a description by Count Pourtalés were published, after his 
death, in 1874. 
This is probably the first specimen listed by Sir Wyville 
Thomson in 1877. 
Figured by J. E. Gray, ‘‘Annals and Magazine of Natural 
History,’’ series 4, vol. 8, 1871, p. 394; (LL. Agassiz) Pourtalés, 
Illustrated Catalogue of the Museum of Comparative Zoology, 
vol. 4, No. 8, February 1874, pl. 10, figs. 1-9. 
Type of Holopus rawsont Gray, 1871. 
In the British Museum. 
3. Barbados. 
Originally in the collection of Sir Rawson W. Rawson. 
This is the second specimen listed by Sir Wyville Thomson, 
which was boiled down to allow of the description of the dis- 
associated parts. 
