PLATE 43. 

 Lovenechinus missouriensis (Jackson). Page 337. 



Figs. 1-5. Same specimen as the photographs of an internal and external mold, Plate 44, figs. 3 and 4 (pp. 344—346). 



Fig. 1 . Drawn from a wax cast of the external mold. X 2.6. Ambulacral plates ventrally are all primaries with pore- 

 pairs uniserial; higher up plates are alternately primaries and nearly or quite occluded (seen better in Plate 42, 

 fig. 1). Dorsally, plates are demi- and occluded, the pore-pairs biserial. In all ambulacral plates the pores he near 

 the interambulacral suture; tubercles are numerous, of uniform size. In all interambulacral areas there are two 

 plates in the basicoronal row, three plates in the second, and four plates in the third row, the fifth column coming 

 in later in the sixth or seventh row. In area I the initial plate of column 5 is tetragonal, a rare variation, and to 

 compensate for the two sides wanting in this plate there are two heptagonal plates, H, lying on its left and right 

 ventral border (compare the similar condition in the introduction of the ninth column in Oligoporus, Plate 50, figs. 

 2, 3, and Melonechinus, Plate 59, fig. 14). 



Fig. 2. Drawn directly from the internal silicified mold, representing the interior of the same plates of which fig. 1 shows 

 the exterior. X 2.6. Ambulacral plates ventrally are all primaries; at the zone XX in area J, plates are alternately 

 primaries and occluded; whereas on the exterior at the same zone, the plates are demi- and occluded (p. 60). Plates 

 opposite interambulacral sutures are fan-shaped, which is not true of the exterior. Pore-pairs are in the middle of 

 the half-area, whereas they are near the interambulacral suture on the exterior. Interambulacral plates arc similar 

 to the same plates of the external view, but are somewhat dislocated. 



Fig. 3. Drawn from a wax cast of the external mold at the mid-zone, representing the detail of a half-ambulacrum and the 

 tenth and eleventh plates from the base of the adradial column of area I. X 2.6. Ambulacral plates are demi- and 

 occluded, pore-pairs are near the interambulacral suture, small tubercles are on all plates. (Compare text-fig. 11, 

 p. 54.) 



Fig. 4. Drawn directly from the internal mold, representing the interior of the same plates as fig. 3. X 3. Pore-pairs 

 are in the middle of the half-area; demi-plates which are opposite the interambulacral horizontal sutures are fan- 

 shaped (p. 60). 



Fig. 5. Drawn from a point in the specimen where the internal and external molds are in place and the former mass of the 

 original plates exists as cavities. X about 5. On the exterior, tubercles are in place, ambulacral plates bevel over 

 the adradials. The pores of ambulacral plates are represented by delicate siliceous rods which pass from the middle 

 of the half-area proximally to near the interambulacral suture distally, a unique condition of preservation. 



Oligoporus (?) minutus Beede. Page 450. 



Fig. 6. Deer Creek Limestone, Carboniferous (Coal Measures), northeast of Topeka, Kansas (after Beede, 1899, Plate 32, 

 fig. 3). Holotype. X 0.9 



Figs. 1-5 drawn by J. Henry Blake; fig. 6 copied by \V. M. Barrows. 



