NORTH AMERICAN EARLY TERTIARY BRYOZOA. 803 



Genus PHORMOPORA Marsson, 1887. 



18S7. Phormopora MARSSON, Bryozoen der schreibkreide der Insel Uiigen, Paleontologische 

 AbhauJlungen, vol. 4, p. :>2. 



Horneridae with cylindrical, dichotomous branches. The apertures are scat- 

 tered irregularly over the obverse face and not in regular transverse rows. The 

 reverse face is marked by small or well-developed tubuli. 



Genotype. Phormopora irregularis Marsson, 1887. Senonian. (After Greg- 

 ory, 1899.) 



The section published by Marsson appears to indicate the lamellar and 

 squamous structure of the Horneridae. but the ovicell is unknown. 



Family FRONDIPORIDAE Busk, 1875. 



1S75. Frondiporidae BUSK, Catalogue of Marine Polyzoa in the collection of the British 

 Museum, pt. 3, Cyclostomata, vol. S, p. 137. 



The larva is elongated; the orifice of the palleal cavity and the orifice of 

 the sack do not occupy exactly the two poles of the embryo. The ovicell is 

 arranged between the fascicles and is traversed by isolated tubes. The tubes are 

 cylindrical. 



The genera belonging to this family are: Frondipora Imperato, 1599. Telo- 

 pora, new genus, and perhaps the following forms: Fasciculipora D'Orbigny, 

 1846, Disco f 'as cigera D'Orbigny, 1853, and Apsendesia Lamouroux. 1821. 



The zoarium is formed of tubes arranged in fascicles. All the tubes have the 

 same diameter throughout ; they are not thinner at the base as in the zoarial 

 forms Entalopora, Idm-onea, etc. In transverse section the tubes of the center 

 have therefore the same diameter as those of the periphery, as in the zoarial 

 forms, Heteropora and Ceriopora. There are therefore cylindrical tubes arranged 

 in bundles. They put forth new tubes by ramification. The basal lamella is very 

 thick and is formed by the exterior wall of long basal tubes without polypide 

 which ramify at nearly the half of their length. Each basal tube takes its origin 

 on the interior of the zoarium which is just the contrary to what is observed on 

 the basal lamella of forms with conical tubes. 



The Frondiporidae are extremely rare in our American Tertiary formations. 

 They appear to have disappeared from our recent American waters ; neither Smitt. 

 Robertson, nor Osborn cites a single species of the family. On the contrary, the 

 specimens of this family swarm in the Mediterranean. 



Genus FRONDIPORA Imperato, 1599. 



159'J. Frondipora IMPERATO. Dell Ilistoria uaturale, p. 031. 



" Frondipora has the ovicell across the anterior surface of a branch, not much 

 raised, and the oeciostome, about 0.12 mm. wide, with the lower edge straight, also 

 is but little raised, and is not attached to a group of zooecia." (Waters.) The 

 fascicles are arranged only on the anterior face of the zoarium. 



