PLATE 34. 

 Maccoya intermedia (Keeping). Page 314 



Fig. 1. Lower Carboniferous, Hook Head, County Wexford, Ireland. Palaeontological Museum, Munich. X 1.2. Four 

 columns of plates in two interambulacral areas. The only ocular preserved is insert. 



Fig. 2. Lower Carboniferous, Hook Head, County Wexford, Ireland. Sedgwick Museum Coll., Cambridge, England. 

 Holotype. X about 4.6. On account of the separation of plates on the adradial suture, the structure is very clear. 

 Ambulacral plates are alternately primaries and occluded, pore-pairs biserial. Interambulacral plates bevel under 

 ambulacrals on the adradial suture, so that here the adradial plates present an inclined face. On the outer border 

 of this face there are impressions of the primary plates only; but on the inner, or proximal border of the inclined face, 

 there are impressions of each ambulacral plate, as on the interior all ambulacral plates cross the half-areas, as 

 shown in fig. 3 (p. 60). 



Fig. 3. Same specimen. X about 4. Seen from the interior, all ambulacral plates cross the half-area, and pore-pairs 

 are uniserial, instead of the plates being alternately primary and occluded, with pore-pairs biserial, as occurs on the 

 outer face of the same plates. 



Maccoya sphaerica (M'Coy). Page 317. 



Fig. 4. Same specimen as photograph, Plate 32, fig. 4. X 1.2. Ambulacral plates are somewhat schematic, and are more 

 correctly given in figs. 5 and 6 (p. 319). Pore-pairs are biserial at the mid-zone, five columns of plates in each inter- 

 ambulacral area. Oculars are all insert, and adorally cover the ambulacra and laterally the interambulacra in 

 part on either side; periproctal plates in place. 



Fig. 5. Same specimen. X 2.6. From the mid-zone, alternate ambulacral plates marginally narrowed and nearly ex- 

 cluded from interambulacral contact; pore-pairs biserial (p. 319). 



Fig. 6. Same specimen. X 2.4. Dorsal portion enlarged. Ambulacral plates dprsally are all primaries and pore-pairs 

 are uniserial. Oculars all insert and cover the ambulacra and laterally the interambulacra in part on either side; 

 against the oculars young interambulacral plates are existent. Plates of the periproct are thick and angular, the 

 most nearly complete of any periproct known in the family (p. 320). In detail the plates were drawn with great care 

 and are more correct than in fig. 4. 



Fig. 7. Same specimen as photograph, Plate 32, fig. 5. Holotype. X 3.5. Ambulacral detail from area marked X in 

 the photograph. Ambulacral plates are alternately primaries and occluded, pore-pairs biserial. In the specimen 

 the ambulacral sutures are difficult to see at most parts (p. 317). 



Fig. 8. Lower Carboniferous, Whatley, near Frome, Somerset, England. University Museum Coll., Strassburg. En- 

 larged. Alternate ambulacral plates are narrowed and nearly excluded from interambulacral contact; pore-pairs 

 biserial (p. 320). 



Fig. 9. Same specimen, enlarged; plates seen from the interior. All pass directly across the half-area and pore-pairs are 

 uniserial. 



Fig. 10. Same specimen. X 4.5. From the dorsal area, where plates are all primaries and pore -pairs are uniserial. 



Maccoya gracilis (Meek and Worthen). Page 323. 



Fig. 11. 1'pper Burlington Limestone, Lower Carboniferous, Burlington, Iowa. Mus. Comp. Zool. Coll. 3,052, holotype. 

 X 2. Ambulacral plates are alternately primaries, and occluded; seven columns of interambulacral plates in area 

 A; the seventh column is interrupted dorsally by one row of six plates, above which it reappears with a pentagonal 

 plate next to the heptagonal plate, H. Same specimen as photograph, enlarged, Plate 35, fig. 1. 



Fig. 12. Same specimen as photographs, Plate 35, figs. 2 and 3 (after Jackson, 1896, Plate 7, fig. 36). External sandstone 

 mold. X 2. Ambulacral detail obscure, restored as indicated by dotted lines in area I, and probably incorrectly 

 (p. 324, compare fig. 11). There are seven columns of plates at the mid-zone as far as shown in each interambulacral 

 area; farther dorsally an eighth column is introduced in each area, and a ninth column, consisting of two or three 

 plates, occurs dorsally in area C. 



Fig. 1 drawn by Anton Birkmaier; figs. 2, 3 and 5-10 from my sketches by J. Henry Blake; fig. 4 by G. C. Chubb; 

 fig. 11 from nature by J. Henry Blake; fig. 12 drawn by J. H. Emerton. 



