RETKCAVA. 
203 ' 
Dimensions. 
FUh Perffcus. 
Diameter of branch ... 
•3--6 
Diameter of zomcia ... 
•14 
Diameter of aperture 
•07 
Distance of transverse series 
•28--34 
Distribution. 
Danian : Faxoe. 
Senonian — Maastriclitiau : Maastricht; Petit-Lauaye ; Faiiquemont ; ■ 
Royan. 
Campanian : Riigen. 
Affinities. 
Tills specie's is nearly allied to Crisidmonea lichenoides^ but it 
differs from it mainly by the Fenestellid aspect of the zoariiim, the 
branches being united by short dissepiments Avhieh do not bear 
apertures. 
LIST OF SPFCTMEXS. 
D. 3227. Two broken zoaria. iNIaastrichter Kreide. iSIaastricht. Van Breda 
Coll. 
D. 6437. Seven fragments (on slide). Maastrichter Kreide. Fauqnemont. 
Busk Coll. 
D. 3576. Three broken zoaria. Maastrichter Kreide. Maastricht. Van Breda 
Coll. 
D. 3675. A fragment of a zoarinm (on slide). iMaastrichter Kreide. 
Maastricht. Van Breda Coll. 
8. Retecava geometrica (von Hagenow), 1851. 
Synonymy. 
Idmonea geometrica, von Ilagenow, 1851. Bit. Maastr. Kr. p. 32, pi. ii. 
fig. 11. 
,, ,, Kade, 1852. Los. Verst. Schanzenb. p. 31. 
,, ,, Hamm, 1881. Bry. mastr. Ob. -Sen. p. 31. 
Crisina ,, d’Orbigny, 1854. Bry. Cret. p. 913. 
Diagnosis. 
Zoarium low and flat, with horizontal or slightly ascending 
branches. The branches consist of a rounded axis on the 
reverse side, and a narrower, triangular obverse portion, to 
