North American index fossils, invertebrates . terior interambulacrum; posterior petals long-est; periproct at proximal end of posterior lunule, close to themouth. Pliocenic-Recent. 35. M. caroliniana McCrady. (Fig. 1926.) Pliocenic. Slightly wider behind; posterior lunule twice as long as others. Differs from the recent M. sexforis Lamarck of the Atlantic coast 38 594 NORTH AMERICAN INDEX FOSSILS. of southern United States and Mexico, in its more orbicular form,more regular convex upper surface, smaller lunules, with slightdepression extending to the margin, and less branched ambulacra!furrows
North American index fossils, invertebrates . terior interambulacrum; posterior petals long-est; periproct at proximal end of posterior lunule, close to themouth. Pliocenic-Recent. 35. M. caroliniana McCrady. (Fig. 1926.) Pliocenic. Slightly wider behind; posterior lunule twice as long as others. Differs from the recent M. sexforis Lamarck of the Atlantic coast 38 594 NORTH AMERICAN INDEX FOSSILS. of southern United States and Mexico, in its more orbicular form,more regular convex upper surface, smaller lunules, with slightdepression extending to the margin, and less branched ambulacra!furrows on under side. Pliocenic marls of South Carolina, etc. XXIII. Encope and thicker than Mellita, more or less subpentahedral,with broad notch or lunule in median line of each ambulacrum,and large lunule in posterior interambulacrum. Pliocenic toRecent. 36. E. macrophora Ravenel. (Fig. 1927.) Pliocenic. Large; posterior lunule broad and surrounded by elevated rim; posterior end gently rounded, not notched; marginal notches shal-. FlG. 1927. Encope macropkcra, lateral and dorsal views. Natural size.(After McCrady.) low, posterior lateral pair deepest; periproct on proximal slope ofposterior lunule. Related to recent E. grandis Agassiz of LowerCalifornia coast. Pliocenic marls of South Carolina. ECHINODERMA TA—ECHINOIDEA. 595 Order SPATANGOIDA EcHiNOBRissus variable, concave beneath. Ambulacra unequal, open atthe end of the subpetaloid parts. Pairs of pores in simple series,the outer ones elongate. Below the subpetaloid parts the pores arein small oblique pairs sometimes united by grooves. Peristomeanterior to center. Periproct at upper end of a groove situatedon the upper surface of the test. Jurassic-Tertiary.
Size: 1422px × 1758px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookidn, booksubjectpaleontology
