on British Paheozoic Crinoids. 297 



(in the absence of a closed oral pyramid), which covers in 

 either the whole of the ventral side or only the peristome. 



3. 1'he want of symmetry, indicated by the presence between 

 two rays of one or more special " anal plates." 



4. The great development of the calyx as compared with 

 that of the arms. 



5. The frequent absence of a distinct articulation between 

 the first and second radials, and of axial canals within the 

 joints of the rays and arms. 



EXPLANATION OF THE PLATES. 



Plate XV. 



Adult spectmem. 



Fig. \. Nine-armed calyx with two brachials. Oarlops Quarry, near 

 Peebles, a, side view, showing the small radial, which bears 

 one arm only ; h, view of the calyx from above, showing the 

 articular faces of the radials. 



Fig. 2. Calyx and lower brachials of another nine-armed example, the 

 most complete yet found. Carlops Quarry, a and b, side views, 

 the former showing the single one-armed radial plate ; c, ventral 

 aspect of the same specimen, showing the second and third bra- 

 chials or arm-joints of three arms. 



Fig. 3. Projection of the calyx and lower brachials of the original of 



Fig. 4. The basal cup as seen from above ; the sutures are quite oblite- 

 rated. Carlops Quarry. 



Fig. 5. Terminal face of a stem-joint, showing rim-like margin, small 

 canal, and central granulation. Oarlops Quarry. 



Fig. 6. Calyx with only three axillary radials and one of the first bra- 

 chials still preserved. Carlops Quany. a, ventral aspect of the 

 calyx ; b, side view, showing the two adjacent simple radials 

 and one first brachial. 



Intermediate specimen. 



Fig. 7. Calyx and upper stem-joints of an irregular example, with small 

 orals and unequally-developed radials. Near Carluke, a, from 

 the side ; b, from above ; the radial on the right bears a very 

 rudimentary brachial. 



N.B. — The figures represent the specimens as magnified nine times. 



Plate XVI. 

 Yozmg specimens. 



Fig. 1. Calyx of a very young individual, with unequally-developed 

 radials and depressed oral pyramid. Catcraig, near Dunbar. 

 X 25. a, from the side ; b, from above. 



Fig. 2. Calyx of another very young specimen, with a large dome of oral 

 plates and very small arm-openings. Whitebaulks, near Lin- 

 lithgow. X 25. a, from the side ; b, from above. 



Ann. & Mag. N. Hist. Ser. 5. Vol. vii. 22 



