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THE VOYAGE OF H.M.S. CHALLENGEE. 
Thyone peruana {Holothuria), Lesson, 1830 ; Selenka, 1867 and 1868. Trepang 
peruviana, Jaeger, 1833. Anaperus peruanus, Troschel, 1846. Anaperu^ 
carolinus, Troschel, 1846. Thyone Carolina, Selenka, 1867. Thyone tenella, 
Selenka, 1867 and 1868. 
Habitat. — Peru (Troschel), Texas (Selenka), South Carolina (Troschel, Pourtales). 
This species seems to be very unsatisfactorily known. I am much inclined to 
refer Troschel’s Anaperus carolinus to Thyone briar eus of Lesueur. Even 
Selenka’s Thyone tenella may without difficulty be referred to the same species, 
■considering that its deposits, figured by Selenka, have certainly supported the 
pedicels and not the body-wall itself, which will easily be seen from the 
elongated curved disks of the tables. Whether Lesson’s and Troschel’s 
Thyone peruana are distinct species or not, cannot be stated at present. 
Thyone cigaro [Anaperus), Troschel, 1846; Selenka, 1867. Stolus cigaro, Selenka, 
1868. 
Habitat. — Labrador (Troschel). 
Seven longer and three shorter tentacles. Pedicels large, crowded. Anus without 
teeth, but with papillse. Calcareous ring unknown. Deposits in the perisome 
absent. 
Thyone glabra [Thyonidium), Ayres, 1854 ; Semper, 1868. 
Habitat. — George’s Bank (Ayres). 
Tentacles — three longer, three smaller, two still shorter, and two very short. Pedicels 
not numerous. Calcareous ring of ten simple pieces, the radial not prolonged 
posteriorly. Deposits of the perisome absent. 
When comparing the imperfect descriptions of these two last forms, one is scarcely 
able to point out a single distinguishing character of importance. The aberrant 
conformation of the tentacles is doubtless an individual abnormahty, and 
the number of Polian vesicles and madreporic canals is known to vary in the 
same species. Both forms agTee in the absence of deposits in the body-wall itself, 
and they are obtained from localities not very distant. 
Thyone pedata. Semper, 1868. 
Habitat. — China Sea (Semper). 
No anal teeth. Ventral pedicels longer and much more crowded than the dorsal. 
Calcareous ring composed of ten pieces, the interradial simple, the radial having 
the ends of their posterior prolongations made up of separate small parts. 
Deposits present, but their shapes unknown. 
