288 Dr. J. W. Gregory — A Revision 



summits of the ridges and never upon their sides. The 

 underside of the zoarium is covered by epitheca. 

 Type species : A. cristata, Lamouroux, 1821. 



1. Apsendesia cri'stata, Lamouroux, 1821. 



Apsendesia cristata, Lamouroux, 1821, Expos, m^th. p. 82, pi. Ixxx. 



figs. 12-14. 

 Discotuhigera cristata, Vine, 1888, Polyz. Caen, Jouru. Northampton. 



Nat. Hist. Soc. vol. v. p. 19. 

 Pelayia clypeata, d'Orbigny, 1849, Prod. Pal. t. i. p. 317. 

 Defrancia clypeata, Bronn & Reamer, 1851, Leth. Geogn. ed. iii. Bd. ii. 



Th. 4, p. 94, pi. xvi. fig. 18. 

 Apsendesia clypeata, E, E. Deslongchamps, 18G5, Jura. inf. Norm., 



Mt^m. Soc. linn. Norm. t. xiv. p. 151. 

 Discotubiyera clypeata, Vine, 1888, op. cit. p. 19. 



Diagnosis. — Zoarium small, dense, and hemispherical ; it 

 grows from a low funnel-shaped central disk ; from this arise 

 the radiating bundles which unite into irregular twisted 

 lamina?. The apertures occur in series or in isolated teeth. 



Distrihution. — England : Inferior Oolite — Forest Marble. 

 Foreign : Bajocian, Germany ; Bathonian, France. 



Family Theonoidae, Busk. 



Diagnosis. — Cyclostomata Tubulata in which the zocecia 

 are simple, short, open tubes; they pass through a Defrancia 

 stage (? always) . The zocecia are monomorphic. 



The apertures occur along raised ridges. 



Genus 1. Actinopora, d'Orbigny, 1852. 



Diagnosis. — Theonoidse in which the zoarium is a flat, 

 simple, adnate disk. The zoarium consists of a central 

 depression, of a rim crossed by radiating ridges, and usually 

 also of a flat peripheral selvage. 



Type species : A. regularise d'Orbigny, 1852. 



1. Actinopora Phillipsi (Haime). 



Lichennpora Phillipsi, Haime, 1854, Bry. Jur., M(5m. Soc. g^ol. France, 

 s^r. 2, t. V. p. 206, pi. x. fig. 10. 



Diagnosis. — Zoarium regular, circular ; radial ridges about 

 22 in number, straight, regular, unbranched. The apertures 

 are biserial. New ridges arise from the interradial valleys. 

 A broad expansion surrounds the zoarium ; this is low and 

 flat, and is not crossed by the radial ridges. 



Distribution. — Great Oolite, Hampton, near Bath, and 

 Richmond boring. 



