Thyone inermis Heller 1868

“Soft sediments, such as crushed shell, quartz sand, and calcareous silt” (Hendler et al 277).

“T. deichmannae is probably a burrowing species and is known to ingest surface deposits (Miller and Pawson 1984). Its stomach contents include foraminiferans, molluscan shell fragments, ostracod valves, echinoid spines, diatom frustules, and some amorphous material. That is unexpected, because the majority of dendrochirote holothurians feed on suspended particles, using their arborescent feeding tentacles. Specimens measuring 16-42 mm can have gonads with mature sperm and eggs. The large, yolky eggs indicate that development is direct, as is common for dendrochirotids (Miller and Pawson 1984)” (Hendler et al 277).

“This species is small, reaching a maximum length of 7 cm (2.8 in). The body is stout, cylindrical, slightly swollen at the middle, and bluntly rounded at both ends. The body wall is thick, smooth, and soft. The numerous tube feet, all with terminal suckers, are scattered over the entire body and lack an ordered arrangement along the radii. Most of the feet remain extended, even in preserved material, giving the species a furry appearance. There are 10 tentacles, of which the ventral pair is smallest. The body wall ossicles are large tables with squarish to rectangular disks, usually perforated with four to eight large holes and up to 10 smaller ones. At the center of the disk there is a spire composed of two pillars and ending in a few small spines. The supporting ossicles of the tube feet are large tables with elongate curved disks and robust spires. T. deichmannae (H. inermis) is drab, with a grayish brown body wall and light gray to light brown tube feet” (Hendler et al 276).

“Previously reported (as T. inermis Heller) from Florida (Jacksonville, St. Augustine, Tampa Bay, Captiva Key), the Florida Keys, Cuba, and Tobago. Material from North Carolina, the northeastern Gulf of Mexico, and Panama is represented in museum (USNM) collections (Miller, previously unpublished). Depth: 6-366 m (20-1,200 ft)” (Hendler et al 277).

At about 50 m depth, on sand, apparently rather rare in the Western English Channel, reported from the Isle of Man but the identification cannot be confirmed