190 THE ECHINODERMS OF TORRES STRAIT. 
Actinopyga parvula. 
Miilleria parvula Selenka. 1867. Zeit. f. w. Zool., 17, p. 314, pl. xvii, figs. 17, 18. 
Actinopyga parvula Verrill. 1867. Trans, Conn. Acad., 1, pt. 2, p. 347.—Fisher. 1907. Proc. U. S. Nat. 
Mus., 32, p. 645, pl. Ixvii, figs. 2-29. 
This species was originally described from specimens from Florida, the largest of 
which was 50 mm. long, but Lampert (1885) records without comment specimens from 
Kosseir on the Red Sea, the Seychelles, and Amboina. Théel (1886) suggested its possible 
occurrence in the Pacific, referring to a specimen 30 mm. long, from Samoa, in the Stock- 
holm Museum. Bedford (1899) records specimens from Funafuti, and Fisher (1907) gives 
an excellent account of 13 specimens from Hawaii. There are specimens in the Museum 
of Comparative Zoélogy from the Tortugas, Florida, the Bahamas, Jamaica, Tobago, the 
Murray Islands, the Kermadec Islands (recorded by Benham, 1911), and Hawaii. 
One very notable feature of all known specimens is their small size and apparent 
immaturity. Another remarkable feature is the close resemblance to Holothuria captiva of 
the West Indies, and to H. difficilis of the Indo-Pacific region. It seems very probable 
that parvula is either the young of a large species, whose calcareous particles undergo an 
extraordinary change with growth, or that it is not phylogenetically an Actinopyga at all, 
but is a Holothuria which has attained calcareous teeth about the anus independently, 
and is most nearly related to H. captiva. Indeed, the resemblance to captiva is one of the 
things which most need investigation. This resemblance is specially emphasized by Ben- 
ham’s (1911) observations on specimens from the Kermadecs, which seem to show regener- 
ation of the posterior half of the body, taken in connection with Crozier’s (1914, p. 8) 
observations on H. captiva at Bermuda. 
This species was not rare at Mer, specimens being found on both sides of the island. 
They occur clinging tightly to the under side of rock-fragments. When touched, they 
eject copious white Cuvier’s organs. The color above is uniformly brown, and beneath is 
yellowish. Few exceed 30 to 40 mm. in length. In all these particulars, as well as in the 
calcareous particles of the body-wall, the resemblance to Holothuria captiva is very striking. 
