FOREIGN OOLITIC ACROSALENIAS. 255 



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



According to M. Desor, this is the smallest species of the genus. It is about the 

 size of a lentil, and is well characterised by its close-set inter-ambulacral tubercles, of 

 which there are from nine to ten in a row. 



Formation. — " Grande Oolite (Vesulien) de la cluse de Pfeffingen pres Bale. 



" Collection.— Museum Bale. Exemplaire unique." Desor. 



Acrosalenia radians, Agassiz. Syn. Hemicidaris radians, Agassiz. Catalogue raisonne 



des Echinides, Annal. Sc. Naturelles, 3 me serie, torn, vi, 

 p. 339. 



Test hemispherical, depressed ; ambulacra narrow, with two rows of small, prominent 

 tubercles ; inter-ambulacral tubercles, nine in a row, large at the equator, small above ; 

 miliary zone with two rows of granules in the middle ; the median suture naked, and 

 depressed at the upper surface ; mouth opening large ; peristome nearly equally decagonal, 

 with wide notches ; discal opening small. 



Formation. — Kellovien de Vivoin, Courgains (Sarthe), Saint- Aubin (Calvados). 



Collections. — MM. Michelin, Rouault; my cabinet. The type specimen kindly sent 

 me by M. Michelin. 



Acrosalenia interpunctata, Quenstedt. Handbuch der Petrefactenkunde, pi. 49, 



figs. 3 and 4. 



Test small and much depressed ; ambulacra very narrow ; inter-ambulacra wide, with 

 large, spaced-out tubercles ; apical disc large; sur-anal plate single, smaller than the other 

 plates ; eight punctuations at the angles between the genitals, oculars, and sur-anal plate ; 

 five of these are at the inner angles of the eye-plates, and three around the circumference 

 of the sur-anal plate ; the five oviductal holes are very small. 



