Report on the zoological collections made in the Indo-Pacific Ocean ...

ECniNODEEMATA. 149belong to an outer, and at others to an inner circle on the disk ; andthat the colour which in some cases is light brown, in others ispurplish grey.Albanj' Island; Torres Straits.Quite recently an example of this species has been receiv^ed fromKurrachee.8. Thyone mirabilis (?).Thyone mirabilis, Ludwig, Semper s Arbeiten, ii. p. 93.The form of the spicules would perhaps allow us to place thesingle specimen hero with doubt referred to this species either withit or with llolotliuria dletricliii of Ludwig, the supporting-rods inthe suckers of the latter not being figured. Though our specimenhas much more the form and colour, so far as one may judge fromthe description, of the Holothurian, the eight large arborescent andtwo small tentacles, the scattered sucker-feet, and the unarmedanal orific exactly determine its generic affinities.Port Denison.9. Thyone sacellus *.Stolus sacellus, Selenka, Zeit. f.iviss. Zool. xvii. p. 355.Thyone rigida, Semper, Holothuvien, p. 66.Thyone sacella, von Marenzeller, Verh, z.-bot. Ges. Wien, 1881, p. 131.Torres Straits.10. Thyone okeni. (Plate IX. fig. D.)The two specimens of this species are in remarkably good conditionfor examination, as one died with its tentacles fully expandedand the other was laid open by the collector.With the exception of the terminal plate in the suckers I havenot been able to detect any calcareous bodies either in the suckersor the integument ; and if any such are present they must be exceedinglysmall and very rare. This characteristic brings thisspecies into proximity to the T. villosa of Semper, where, as in this,the suckers are very closely packed.Elongated in form, very dark brown in colour (in spirit), tentaclesof about the same shade ; suckers closely packed and distributed overthe whole body, their radial arrangement in the region of the anusvery obscurely indicated. Anus without teeth. Retractors insertedvery nearly as far back as the middle of the body. Calcareous ringof ten pieces, the radial similar to the interradial, elongated, andwider below than above (fig. I)). Calcareous plating extends someway along the enteric tract (fig. D). Genital tubes numerous, veryslender and long, inserted behind the middle point of tlie length of* Prof. Selenka has been kind enough to inform me that sacellus, as usedby him, is a diminutive form of saccus, not of sacer.