PLATE XXIV. 



The Lettering is the same in all the Figures, 



A. Axial cord of the ray. cv. Cirrus-vessel 



ai. Primary interradial cords. 



ar. The secondary (radial) cords resulting from their bifurca- 

 tion. 



£. Basal. 



ca. Fibrillar sheath round vascular axis of stem. 



'ca'. Its radiating extensions. 



ceo. Interradial portion of the circular commissure. 



ch. Cavities of the chambered organ. 



ch'. Their downward prolongations into the stem. 



cJic. Fibres of connective tissue which traverse the fibrillar 



envelope of the chambered organ. 

 chn. The nodal enlargements of the peripheral vessels of the 

 stem {ch'). 



ico. Intra-radial portion of the circular commissure. 



i. Interi'adial ligament. 

 I. Basiradial ligament. 



lb. Interbasal ligament. 



Id. Dorsal ligament. 



Is. Interarticular ligament of stem. 



27. Pigment gi'anules. 

 ill. First radial. 



rp. Plug of calcareous tissue occupying the central funnel of 

 the calyx. 



V. Central vascular axis of stem. 



X. Plexiform gland. 



Pentacrinus wyville-thomsoni, Jeffreys. 



Fig. 1. Horizontal section of an upper internodal joint. 



Fig. 2. The central part of the same section, enlarged, 



Fig. 3. Horizontal section through the upper part of a nodal joint, 



Fig. 4. Horizontal section of a nodal joint at the origin of the cirrus- 

 vessels, . . . . . . . X 90 107 



Fig. 5. The central part of a horizontal section through an internodal 



joint near the top of the stem, . . . . x 90 23 



In this figure ch should be cJ/', as in fig. 2. 



Figs. G-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, ...... 



Fig. 7. Section through the upper part of the basal ring, 



Fig. 8. Section through the lower part of the radials, . 



Fig. 9. Section through the middle of the radials. 



