IDMONEA. 135 



Idmonea triquetra, Morris, 1843, Cat. Brit. Foss. p. 40. 



,, ,, Michelin, 1846, Icon. Zooph. p. 234, pi. Ivi. fig. 16. 



,, ,, Bronn, 1848, Nomencl. p. 607. 



,, ,, Bronn, 1849, Enum. p. 140. 



,, ,, D'Orbigny, 1849, Prod. Pal. t. i. p. 317. 



,, ,, Bronn and Romer, 1851, Leth. Geogn. ed. 3, Bd. ii. Th. 4, 



p. 87, pi. xvi. fig. 11. 



,, ,, D'Orbigny, 1852, Pal. fran^. Terr. cret. t. v. p. 729. 



,, ,, Haime, 1854, Bry. jurass. : Mem. Soo. geoL France, ser. 2, 



t. v. p. 171, pi. vii. fig. 1. 



,, ,, Morris, 1854, Cat. Brit Foss. ed. 2, p. 125. 



,, ,, Vine, 1884, Polyz. Richmond boring: Quart. Journ. GeoL 



Soc. vol. xl. p. 790. 

 ,, Vine, 1888, Polyz. Caen: Journ. Northptn. Nat. Hist. S<>c. 



vol. v. p. 7. 



non ,, ,, Walford, 1889, Bry. Shipton, pt. i. : Quart. Journ. GeoL 



Soc. vol. xlv. pp. 568-9, pi. xviii. fig. 13 ; pi. xix. figs. 3, 4. 

 ,, Woods, 1891, Cat. Type Foss. Woodw. Mus. p. 48. 



,, ,, Gregory, 1896, Rev. pt. v. : Ann. Mag. Nat. Hist. ser. 6, 



vol. xvii. p. 194. 

 Reptotubigera D'Orbigny, 1852, op. cit. p. 751. 



Pictet, 1857, Traite Pal. ed. 2, t. iv. p. 139. 

 Idmonea gracilis, D'Orbigny, 1849, op. cit. p. 317. 



DIAGNOSIS : 



Zoarium composed of triangular branches, beside each of which 

 is a thin flat selvage. The branches dichotomize repeatedly. 



Zocecia from four to seven in each series. Peristomes open 

 along the summit of a low ridge. Zooecia slender and cylindrical 

 in adult; short, thick, and angular in young stages. "Walls 

 punctulate. 



DISTRIBUTION. 



ENGLAND : 



Bradford Clay : Bradford ; Box ; Pound Pill. 



Great Oolite : Minchinhampton ; Richmond boring. 

 FOREIGN : 



Bathonian Calcaire a polypiers : Ranville, Luc, and Caen, in 

 Calvados, France. 



Description of Figure. Plate VII. Fig. 6. Part of a young 

 zoarium, X 32 dia. Great Oolite : Minchinhampton. Byne Coll. 

 20730. 



Affinities. This is the type species of the genus, and it is fairly 

 common in the Lower Oolitic rocks of England and France. 



