206 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



closing distally, narrow poriferous zones, ambulacral plates beyond 

 petals single pored ; periproct marginal, longitudinal ; peristome an- 

 terior, pentagonal, usually with rim around opening; bourrelets ver- 

 tical, not inflated ; phyllodes single pored, narrow, few occluded 

 pores ; buccal pores present ; adoral tubercles only slightly larger 

 than adapical ; very narrow, naked, often pitted medial zone in inter- 

 ambulacrum 5 adorally. 



Comparison with other genera. — Ilarionia is very similar to Gito- 

 lampas, but differs in having less developed phyllodes and bourrelets. 

 In Ilarionia the phyllodes are narrow with very few occluded pores, 

 whereas in Gitolampas they are widened with a regular inner series 

 of pores in each half -ambulacrum. Furthermore, in Ilarionia there 

 is a narrow naked medial zone in interambulacrum 5 adorally, but 

 none in Gitolampas. There is usually a rim surrounding the peristome 

 in Ilarionia. 



Ilarionia is distinguished from Pliolampas by its narrower porif- 

 erous zones, more closed petals, marginal instead of inframarginal 

 periproct, and less developed bourrelets and phyllodes. 



Remarks. — Mortensen (1948, p. 255) and Lambert and Thiery 

 (1921, p. 369) state that there is no floscelle in Ilarionia. They were 

 probably misled by Dames' erroneous figure of the peristome of the 

 type species. I have seen specimens of both the type species and 

 Ilarionia sindensis Duncan and Sladen, and in both species there are 

 vertically sided bourrelets and slightly developed phyllodes. 



Range and distribution. — Eocene of Europe, India, Madagascar. 



DESCRIPTION OF TYPE SPECIES 



ILARIONIA BEGGIATOI (Laube) 



Plate 39, figures 4-10; text figure 170 



Echinanthus beggiatoi Laube, 1868. Sitzungsb. Kais. Akad. Wiss., Math.- 

 Naturw., vol. 29, p. 22. 



Material. — Two specimens studied from Geologisch-Palaontolo- 

 gisches Institut und Museum der Humboldt-Universitat zu Berlin, 

 One of the specimens figured by Dames (1878, pi. 5, fig. 2), the other 

 mentioned by him in his description. 



Shape. — Medium size, largest of two specimens studied 44 mm. 

 long, elongate, anterior margin smoothly rounded, posterior pointed 

 when viewed from above, blunted when viewed from below; sides 

 steep ; adoral surface flat, peristome almost flush with test. 



