112 THE VOYAGE OF H.M.S. CHALLENGES. 



Cuboides crystallus, n. sp. (PI. XLIL). 



Habitat. — Tropical and Subtropical Atlantic, Station, 352; lat.' 10 °55' N., long. 

 17°46'W. Surface. 



Canary Islands, Lanzerote, February 1867 (Haeckel). 



Bract (fig. 9, u, lateral view from the right side; fig. 10, u, dorsal view; fig. 13, u, basal 

 view ; fig. 14, w, apical view ; figs. 11, 12, a younger specimen, seen from the left and 

 from the dorsal sides respectively). — The hydrophyllium or bract is very large (10 to 

 12 mm. diameter), nearly cuboidal, with six flattened, slightly concave, quadrangular faces, 

 twelve serrate, slightly concave edges, and eight prominent, three-sided pyramidal 

 angles. The six faces are of nearly equal size, the apical face (ua) somewhat smaller, 

 and the basal face a little larger than the four lateral faces (ud, dorsal ; uv, ventral ; ux, 

 right ; id, left). The basal, inferior or distal face is occupied by a wide, flatly conical, 

 subumbrellar cavity (ui), its apex reaches the centre of the cube. 



Phyllocyst (cs). — The apical canal of the bract, or the phyllocyst, consists of two 

 very different parts, the axes of which are nearly perpendicular one to another. The 

 slender apical part is subvertical, spindle-shaped, includes a fusiform oleocyst (co)', and 

 touches with its apex the centre of the concave apical face of the bract (ua). The 

 dilated basal part of the phyllocyst, however, is divided into two broad ovate horizontal 

 lobes (cs", right ; cs', left) ; these are filled up with large clear entoderm cells, directed 

 towards the ventral face of the bract (uv), and embrace the uppermost part of the 

 peduncle of the siphon' (s). 



Siphon (s). — The siphon or polypite is pyriform, very contractile, suspended in the 

 top of the subumbrellar cavity, and exhibits a pale yellowish colour. Its short pedicle 

 bears at its thickened base, on its dorsal side, the tentacle (t) ; on its ventral side are 

 placed one or two gonophores (g). 



Tentacle (t). — The single tentacle of this cuboidal Eudoxia is usually coiled up and 

 hidden in the dorsal part of the infundibular cavity, behind the siphon. The tentilla or 

 secondary filaments (fig. 16) have a thin pedicle (ts) and a simple terminal filament (tf), 

 and between them a large reniform sacculus. This cnidosac has a leather-yellow or 

 reddish-yellow colour, and contains on the convex dorsal side numerous (six to nine) 

 rows of medial cnidocysts (km), and on each side of this battery, in the proximal part, a 

 series of six to nine very large, spindle-shaped, lateral cnidocysts (kg) ; at the distal end 

 a small group of small pyriform cnidocysts. 



Gonophores. — The Eudoxise develop in the bracteal cavity, on the ventral side 

 of the siphon, either male or female gonophores. The young Eudoxise (figs. 11, 12) 

 exhibit only one gonophore, the older two or three (figs. 9, 10, 13, 14). The umbrella of 

 the gonophores (or the gonoealyx) is quadrangular, slightly bilateral, a little asymmetrical. 



