A, Axial cord of the ray. cv. Cirrus-vessel. 
ai. Primary interradial cords. ico. Intra-radial portion of the circular commissure. 
. The secondary (radial) cords resulting from their bifurca- | JZ. Interradial ligament. 
tion. 1, Basiradial ligament. 
. Basal. 7b. Interbasal ligament. 
. Fibrillar sheath round vascular axis of stem. id. Dorsal ligament. 
. Its radiating extensions. Zs. Interarticular ligament of stem. 
cco. Interradial portion of the circular commissure. p. Pigment granules. 
ch. Cayities of the chambered organ. R,. First radial. 
ch’. Their downward prolongations into the stem. rp. Plug of calcareous tissue occupying the central funnel of 
che. Fibres of connective tissue which traverse the fibrillar the calyx. 
envelope of the chambered organ. V. Central vascular axis of stem. 
chn. The nodal enlargements of the peripheral vessels of the | X. Plexiform gland. 
stem (ch’), 
PLATE XXIV. 
The Lettering is the same in all the Figures. 
PENTACRINUS WYVILLE-THOMSONI, Jeffreys. 
Diam. Page 
Fig. 1. Horizontal section of an upper internodal joint, x, 15 23 
Fig. 2. The central part of the same section, enlarged, x 90 120 
Fig. 8. Horizontal section through the upper part of a nodal joint, x 90 107 
Fig. 4. Horizontal section of a nodal joint at the origin of the cirrus- 
vessels, se EXD) 107 
Fig. 5. The central part of a horizontal section through an internodal 
joint near the top of the stem, xe 350 23 
In this figure ci should be ch’, as in fig. 2. 
Figs. 6-9. Four out of a series of nearly horizontal sections through the calyx. 
Fig. 6. The centre of a section through the lower part of the basal 
ring, x 90 105 
Fig. 7. Section through the upper part of the basal ring, xe 124 
Fig. 8. Section through the lower part of the radials, . ae 125 
Fig. 9. Section through the middle of the radials, x Cl 125 
