104 FOREIGN OOLITIC HEMICIDARIS. 



Hemicidaris alpina. Agassiz, Echinodenn. Foss. Suisse, II, p. 52, t. 18, figs. 19 — 22. 



Test large, sub-conoidal. Ambulacra wide, with six pairs of large, close-set serai- 

 tubercles at the base; two marginal rows of round granules above, and between these 

 four or five rows of a microscopic miliary granulation. Inter-ambulacra with eight tubercles 

 in each column. Mouth opening large, peristome deeply notched, lobes nearly equal. 

 Apical disc of moderate size, elements nearly equal. 



Dimensions. — Height, nine tenths of an inch ; breadth, one inch and one quarter. 



Formation. — "Portlandien moyen (Kimmeridgian) de Gesne et des Ormonds (Alpes 

 Vaudoises), tres rare." — Desor. 



Collections. — Museums of Berne and Zurich 



Hemicidaris Thurmanni. Agassiz, Echinoderm. Foss. Suisse, II, p. 50, t. 19, 



figs. 1—3. 



Test small, depressed. Ambulacral areas narrow and very flexuous, with small semi- 

 tubercles at the base, and minute marginal tubercles above. Inter-ambulacral areas wide, 

 with three or four tubercles only in each row, which have very prominent bosses ; the 

 areolas are each surrounded by a complete circle of scrobicular granules. Mouth opening 

 large, peristome divided by notches into ten nearly equal-sized lobes. 



Dimensions. — Height, eleven twentieths of an inch ; breadth, one inch and one tenth. 



Formations. — " Portlandien moyen (Marnes Pteroceriennes) du Bannepres Porrentruy, 

 de Delemont, du Jura Vaudois, des environs de Salins." — Desor. 



Collections. — Museums of Neuchatcl and Bale. Coll. Michelin, Thurmann ; common. 



Hemicidaris Hofmanni. Syn. Cidarites Hofmanni. Roemer, Oolitic Gebirges, p. 25, 



t. 1, fig. 18. 



Test small, sub-spheroidal, flat at the summit. Ambulacral areas narrow, convex, and 

 slightly flexuous, with five or six pairs of semi-tubercles at the base, and two rows of small 



