254 FOREIGN OOLITIC ACROSALENIAS. 



towards the disc and peristome ; miliary zone moderate in width, and composed of four 

 rows of granules ; mouth opening large, peristome decagonal ; discal opening large. 



Dimensions. — Height, eight tenths of an inch ; transverse diameter, one inch and four 

 tenths. 



Formation. — Cornbrash (Bathonien) Marquise. 



Collections. — British Museum, Neuchatel Museum, M. Bouchard, M. Michelin, my 

 cabinet. M. Desor states that this species is often ticketed in Conti- 

 nental collections by mistake, Hemicidaris Luciensis, d'Orbigny ; the 

 latter is altogether a different urchin. 



Acrosalenia granulata, Merian. Syn. Hemicidaris granulata, Merian, in Agassiz's 



Catalogue raisonne, Annal. Sc. Naturelles, 

 tome vi, p. 339, 3 mc serie. 



A small, depressed species. The ambulacral tubercles are so small that they resemble 

 miliary granules ; the tubercles of the inter-ambulacral areas are disposed at some 

 distance apart. 



Formation. — " Grande Oolite (Vesulien) de Gensingen (Argovie), avec les Disaster 

 analis, Holectypus depressus," &c. Desor. 



Collections. — Museum Bale, Collection M. Maesch. Very rare. 



Acrosalenia elegans, Desor. Synopsis des Echinides Fossiles, p. 143. 



This species, according to M. Desor, resembles the preceding. It is larger, but has a 

 small mouth opening, and the ambulacral tubercles are excessively small. 



Formation. — " Grande Oolite (Vesulien) du Romberg (Argovie), avec la precedente. 



" Collection. — Maesch." Desor. 



