FOREIGN OOLITIC PSEUDODIADEMAS. 141 



primaries nearly equal the latter in size ; those near the centro-suture are much smaller ; 

 miliary zone covered with small granulations above ; pores strictly unigeminal ; areolas 

 confluent at the equator, separated by small granules above ; mouth opening small ; 

 peristome scarcely notched. 



Dimensions. — Height, three tenths of an inch ; transverse diameter, seventeen 

 twentieths of an inch. 



Formation. — " Jura superieur du Dept. du Doubs. Tres rare." Desor. 



Collection. — Museum Neuchatel, Coll. Renaud-Comte (Musee Besancon). 



PsEUDODiADEMA PLANissiMUM, Agassiz. Syn. Tetragramma planissimum, Agass., Echinod. 



Foss. Suisse, part ii, tab. 14, figs. 1 — 3. 



Test small, circular, very much depressed; inter-ambulacra with four rows of 

 secondary tubercles, which at the base and equator equal the two rows of primary 

 tubercles in size ; these divisions of the test therefore support six rows of equal-sized 

 tubercles ; in the upper part of the area the secondary tubercles become much smaller ; 

 ambulacra with two rows of tubercles as large as those in the inter-ambulacra ; miliary 

 zone very narrow ; mouth opening small ; peristome scarcely notched. 



Dimensions. — Height, one fifth of an inch ; transverse diameter, four fifths of 

 an inch. 



Formation. — " Portlandien moyen (Calcaire a Tortues) de Soleure, Marnes Strombiennes 

 de Porrentruy." Desor. 



Collection. — Museum Neuchatel, Coll. Gressly, Thurmann. Very rare. 



C. Pores bigeminal in the upper part of the zones ; inter-ambulacra with tioo roios of 



secondary tubercles. 



PsEUDODiADEMA suBANGULARE, Goldfuss. Syn. Cidarites subangularis, Goldfuss, 



Petrefacta, Germanise, tab. 40, fig. 8. 



Test pentagonal, depressed ; ambulacra one half the width of the inter-ambulacra, with 

 two rows of tubercles 10 or 12 in each row; inter-ambulacra with two rows of primary 

 tubercles 10 or 12 in each row, and two rows of small secondary tulDcrcles on the zonal 

 sides of the primaries, extending three fourths of the length of the area ; bosses small 



