Genus 548. Lychnocanium,[[165]] Ehrenberg, 1847, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 54.
Definition.—Sethopilida (vel Dicyrtida triradiata aperta), with three solid terminal feet on the peristome. No thoracic ribs. Cephalis with a horn.
The genus Lychnocanium, very rich in common living and fossil forms, comprises those Sethopilida in which the thorax bears three simple terminal feet around the mouth, but no lateral ribs in its wall. It has therefore been probably derived from Dictyophimus by reduction and loss of these three lateral ribs. The mouth is commonly more or less constricted. The three feet surrounding it are sometimes divergent, straight or curved, at other times parallel and vertical, straight, or curved and convergent. The central capsule exhibited in some living species three or four distinct lobes, filling up the upper half of the thorax.
Subgenus 1. Lychnocanella, Haeckel.
Definition.—Feet divergent, straight or scarcely curved; their terminal distance greater than their basal distance.
1. Lychnocanium lanterna, n. sp. (Pl. [61], fig. 7).
Shell conical, rough, with slight collar stricture. Length of the two joints = 1 : 3, breadth = 1 : 3. Cephalis with a stout pyramidal horn of the same length. Thorax pear-shaped, twice as broad as the constricted mouth, with regular, circular pores of the same breadth as the bars. Three feet pyramidal, little divergent, straight, about as long as the cephalis.
Dimensions.—Cephalis 0.03 long, 0.03 broad; thorax 0.09 long, 0.08 broad.
Habitat.—Central Pacific, Stations 263 to 268, depth 2650 to 2900 fathoms.
2. Lychnocanium continuum, Ehrenberg.