132 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



many pores scattered irregularly between these two series, whereas 

 in S. lamberti and 5. galeatus there are one-quarter as many pores 

 and all of them are in two regular series. An even more striking 

 feature in Gongrochaniis herschelianus is the prominent bulge in the 

 median area of each phyllode. This feature is not present on any 

 of the species of Stigmatopygus, or as far as I know, in any other 

 echinoid. 

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



DESCRIPTION OF TYPE SPECIES 



GONGROCHANUS HERSCHELIANUS (M'Clelland) 

 Plate 19, figures 4-6 ; plate 20, figure i ; text figure 1 18 



Cyrtoma herscheliana M'Clelland, 1840. Calcutta Journ. Nat. Hist., vol. i, 

 No. 2, pp. 185-187, pi. 5, figs. 1-3. 



Material. — I studied the three syntypes of Forbes' (1846, p. 162, 

 pi. 19, fig. I, published in 1856) Niicleolites elatus, a junior subjective 

 synonym of Gongrochanus herschelianus. These specimens are in 

 the British Museum (Natural History). Specimen No. E 42324 is 

 herein designated the lectotype of Forbes' species. His figures are 

 a reconstruction, as none of the three specimens shows all the char- 

 acters depicted on one of his figures. All the specimens are poorly 

 preserved, being badly weathered and fractured. 



Shape. — Large, elongate to broad, highly inflated, with fiat or 

 slightly depressed adoral surface. 



Apical system. — Slightly posterior to slightly anterior to center, 

 tetrabasal, according to Stoliczka (1873, P- ^8) only three genital 

 pores, no pore in genital 2. 



Ambulacra. — Petals broad, closed, petal HI longer than others. 

 Interporiferous zones broad, tapering distally ; pores conjugate, outer 

 pore slitlike, inner round to slightly elongated transversely. 



Periproct. — Supramarginal, in groove forming notch, extending 

 to posterior margin, opening longitudinal to circular. 



Peristome. — Central, wider than high. 



Floscelle. — Bourrelets strongly developed, jutting into peristome, 

 toothlike. Phyllodes very broad, with many single pores arranged 

 regularly in two series in each half-ambulacrum with many pores 

 scattered irregularly between these series : approximately 26 pores 

 in each outer series, 15 in each inner (text fig. 118) and 26 irregu- 

 larly scattered between ; pores widely separated from edge of peri- 



