28 
THEONOID^. 
.RETENOA/ Gregory, 1909. 
[New Cret. Bit. : Geol. Mag. dec. 5, vol. vi. p. 62.] 
Synonym. 
Frondipora, pars, d’Orbigny, 1853. 
Diagnosis. 
Tlieonoidse with an erect frondose zoarium, composed of a net- 
work of dichotomous, anastomosing branches. The apertures 
all open on one face of the zoarium. 
Type Species. 
Retenoa campicheana 1853. Xeocomian: Sainte-Croix, 
Switzerland. 
Afeinities. 
This genus is a Theonoid with an erect reticular zoarium. The 
type species was ■ placed by d’Orbigny in the Fro7idipora of 
de Blainville. Frondipora, however, is an Osculiporid nearly 
allied to Homoeosolen. Its type species is the common Medi- 
terranean F, reticulata (L.), which has been well figured, as for 
example by Lamouroux and Busk ; it has a frondose zoarium, 
with the apertures opening in tufts or on an irregular ridge along 
the obverse face of the zoarium. Frondipora may be regarded as 
an Homoeosolen in which the apertures are confined to a sinuous 
broken ridge, instead of opening on the whole obverse surface and 
on lateral processes. 
D’Orbigny® founded the genus Rhyzopora on the type species of 
Frondipora, so the two names are necessarily synonyms, as he 
recognized in 1853.* 
Retenoa campicheana (d’Orbigny), 1853. 
, Synonymy. 
Frondipora campicheana, d’Orbigny, 1853. Bry. Cret. p.678, pi. 783, figs. 12-16. 
,, ,, Canu, 1902. Bry. foss. i., Coll. Camp. : Bull. Soc. 
« geol. France, ser. 4, vol. ii. p. 11. 
’ The name is given as an abridgment of Rete-theonoa, the theonid with 
a net -shaped zoarium. 
2'Lamouroux : Exposition Metli.” Polyp, p. 41, pi. Ixxiv. figs. 10-13. 
C. Busk: Cat. Mar. Polyz. B.M. pt. iii., Cycl. 1875, p. 38, pi. xxi. 
^ D’Orbigny. Descrip. Genres nouv. Bryoz. : Kev. Mag. Zool. ser. 2, vol. i. 
(1849), p. 504'. 
D’Orbigny. Bry. Cret. p.' 677. 
