NO. 3 CASSIDULOID ECHINOIDS — KIER I35 



differs in having a marginal to inframarginal periproct, and a low, 

 very elongate test. 



Range and distribution. — Upper Cretaceous (Senonian) of Persia 

 and Guatemala. 



DESCRIPTION OF TYPE SPECIES 



PYGUROSTOMA MORGANI Cotteau and Gauthier 



Plate 19, figures 1-3; text figure 117 



Pygtirostoma morgani Cotteau and Gauthier, 1895. Mission scientifique en 

 Perse par J. de Morgan, vol. 3, pt. 2, Paleontologie, p. 52, pi. 8, figs. 1-5. 



Material. — One topotypic specimen studied from the Lambert Col- 

 lection, at the Sorbonne, and one in the Museum National d'Histoire 

 Naturelle, Paris. 



Shape. — Medium to large (65 mm. long), elongate, with slightly 

 pointed posterior margin, low, greatest width posterior to center, 

 greatest height at center ; adoral surface slightly depressed. 



Apical system. — Slightly anterior, tetrabasal, four genital pores. 



Ambulacra. — Petals broad, equal, flush with test, extending two- 

 thirds distance to margin, with broad interporif erous zones ; petal III 

 open, all other petals closing distally; poriferous zones broad, taper- 

 ing distally, pores conjugate, outer pore slitlike, inner pore slightly 

 elongated transversely, zones of equal length. 



Periproct. — Marginal to inframarginal, longitudinal, very narrow. 



Peristome. — Anterior, pentagonal, wider than high. 



Floscelle. — Well developed (see pi. 19, fig. 3). Bourrelets strongly 

 inflated, toothlike; phyllodes very broad (text fig. 117), deeply de- 

 pressed between bourrelets, single pored with many pores : approxi- 

 mately 15 in each outer series, 25 scattered irregularly in inner area 

 in each half -ambulacrum. Buccal pores small, widely separated from 

 peristome edge. Sphaeridia in two rows in middle of ambulacrum. 



Occurrence. — Upper Cretaceous (Senonian) of Persia. 



Location of type specimen. — Not found by this author. 



Remarks. — This species has always been considered as having a 

 monobasal apical system. On the specimen I studied in the Museum 

 National d'Histoire Naturelle only a portion of the system was 

 visible, but without any doubt it was tetrabasal. 



Genus LEFORTIA Cossman 



Lefortia Cossman, 1901 (January). Rev. crit. paleozool., vol. 5, p. 5<S. Type 

 species by monotypy, Pomelia delgadoi De Loriol. 



