Dimensions.—Length of the shell 2.2 to 2.6, breadth 1.7 to 1.9.
Habitat.—Central Pacific, Stations 271 to 274, depth 2350 to 2750 fathoms.
3. Cœlospathis octodactyla, n. sp. (Pl. [128], fig. 9).
Shell-mantle about as long as broad, in the frontal perimeter nearly isosceles triangular, very similar to the two preceding species; it differs from them in the following characters: all eight styles have nearly equal size, and each bears six to eight pairs of branches. The eight fingers of the terminal coronets diverge nearly in one plane, and are not curved in a zigzag manner, but armed with alternate, slender, recurved hooks, which are larger than in the two preceding species, and geniculate at the base; the distal end of each finger bears a verticil of eight to ten very small divergent teeth, which are not recurved (fig. 9).
Dimensions.—Length of the shell 2.4, breadth 2.2.
Habitat.—North Pacific, Station 252, surface.
Genus 736. Cœlodecas,[[352]] n. gen.
Definition.—Cœlographida with an odd sagittal frenulum on each galea and an outer lattice-mantle, armed with ten styles (one odd and four paired styles on each valve).
The genus Cœlodecas is closely allied to Cœlographis, but differs from it in the development of a new pair of styles on each valve. These are placed between the odd nasal and the paired tergal styles, are usually directed laterally, parallel to the frontal axis of the body, and may therefore be called frontal or lateral styles. The total number of coronal styles is therefore ten.
1. Cœlodecas sagittaria, n. sp. (Pl. [126], figs. 2a, 2b).