2l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I44 



Synonym of STUDERIA 



Tristomanthtis Bittner, 1892. Sitzungsb. Kais. Akad. Wiss., Math.-Nat. Classe, 

 vol. loi, Bd. 3, p. 355. Type species by subsequent designation, Lambert (1906, 

 p. 41), Nucleolites subcarinatus Goldfuss. 



DESCRIPTION OF TYPE SPECIES 



STUDERIA SUBCARINATUS (Goldfuss) 



Plate 41, figures 6-9; text figure 178 



Nucleolites subcarinatus Goldfuss, 1826. Petrefacta Germaniae, p. 142, pi. 143, 

 fig. 10. 



Material. — Two specimens studied from the Lambert Collection, 

 Sorbonne, Paris, and four specimens in the U. S. National Museum. 



Shape. — Medium size, oval, posterior slightly truncated, slight ridge 

 in median suture of interambulacrum 5 on adapical side, greatest 

 width at center, greatest height posterior ; peristome deeply depressed. 



Apical system. — Slightly anterior, monobasal, only three genital 

 pores, no pore in genital 3. 



Ambulacra. — Petals equal length, open, interporiferous zones same 

 width as poriferous zones; pores conjugate, outer pore slightly elon- 

 gated transversely, conjugation grooves deep; pore pairs widely 

 spaced; single pores in ambulacral plates beyond petals. 



Periproct. — Slightly supramarginal, longitudinally elongate, with 

 groove extending from adoral side of opening to posterior margin. 



Peristome. — Central to slightly anterior, deeply depressed, pentag- 

 onal, higher than wide. 



FlosceUe. — Bourrelets very strongly developed ; phyllodes widened, 

 single pored (text fig. 178), slightly developed but with large pores; 

 five or six in each outer series, one to two in each inner series ; buccal 

 pores present. 



Tiiherculation. — Adorally tubercles only slightly larger than adap- 

 ically ; no naked, granular zone in interambulacrum 5. 



Occurrence. — Oligocene of Germany. 



Location of type specimen. — Not known. 



Remarks. — There is little doubt that Tristomanthtis is a synonym 

 of Studeria. The type species of both genera are very similar, having 

 open petals with deep conjugation grooves, only three pores in the 

 apical system with no pore in the left anterior genital plate, a mar- 

 ginal longitudinal periproct, a peristome higher than wide, deeply 

 depressed, well-developed bourrelets and similar phyllodes. 



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