THE EED CHALK OF HUNSTANTON. 479 



Genus Unitubigera, d'Orbigny. 



1852. Unitubigera^ d'Orb. Terr. Cret. v. p. 759. 



D'Orbigny founded this genus to include a very peculiar group of 

 fossil Polyzoa. The zonrlum was fixed (parasitic ?) on a large num- 

 ber of fossils ; the zocec/ia were disposed in primary rays, radia- 

 ting from the centre, with intermediate rays between the primaries 

 in the wider parts of the zoarium. On the border, or outer edge, 

 of the zoarium were a number of " germes de cellules," probably 

 remains of former colonial (?) growths. D'Orbigny gives a list of 

 eight species of Lichenopora and JDefrancia, from other authors, 

 that may be placed under this generic head, and one of these is the 

 peculiar Ceriopora discif omits of Goldfuss. In the Paleont. Prang. 

 Terr. Cret., d'Orbigny describes and illustrates two species only, 

 Unituhigera discus, d'Orb., p. 760, pi. 763. figs. 4-6, and Uai- 

 tvhigera jpapyracea, d'Orb. ; and to this latter species a single Eed- 

 Chalk Polyzoon seems to be related. In Mr. Etheridge's list 

 (Bibliograph. 36, p. 590) he uses d'Orbigny's generic name for a 

 Lower-Greensand species. 



29. Unitubigera papyracj:a, d'Orb. 



1850. Actinopora papyracea, d'Orb. 



1852. Unitubigera papyracea, d'Orb. Terr. Cret. v. pi. 64)^. figs. 

 12-14. 



The example which I place under the above name is almost 

 unique. The zoarium is disciform, slightly raised above the surface 

 of the fossil to which it is attached, and is wholly adherent. Zooecia 

 disposed in linear rays, radiating from the centre of the zoarium, 

 with intermediary rays when the zoarium begins to widen out 

 towards the margin ; short, punctate, contiguous. The raised and 

 slightly slanting border is composed of what d'Orbigny calls 

 " germes de cellules," already referred to. 



Habitat. On Terebratida biplicata. Fossil IS'o. 29. 



Horizon. Hed Chalk, Hunstanton ; Meudon, in 22 stage Seno- 

 nian (d'Orb.). 



The following two species (?), which I do not attempt to classify, 

 are placed here temporarily : — 



30. Entalophora (?), Lamouroux, sp. 



This and the following species (?) I cannot attempt to identify 

 with any known Polyzoa : but, because of their rarity, they ought 

 to be recognized here, in the hope that better examples may be 

 sought for and found. 



Habitat. On Spondylus. Fossil No. 30 i. 



Horizon. Eed Chalk, Hunstanton. 



Ee-examining some of Mr. Jesson's fossils, I find another obscure 

 specimen rather better 2)reserved. 



