84 WINCHELL AND MARCY ON FOSSILS FROM THE 



Cladopora Hall. 



Cladopora lichenoides W. and M. 



Plate II. figure 1. 



Polypary consisting of a mass of crowded cylindrical tubes arranged in ramose and folia- 

 ceous forms, both forms being sometimes united in one specimen. The earlier growth, in 

 one of our specimens, is explanate. The cells are elongated, obliquely horizontal, crowded, 

 overlapping, with their mouths opening obliquely through the epitheca. The frond devel- 

 ops into an irregularly undulate form, sometimes dividing, and some of the lobes bending 

 round laterally, after the manner of one or two turns of an Archimedes. From the border of 

 the frond arise terete, bifurcating branches, with the mouths opening on all sides. All the 

 cell-mouths are somewhat crescentiform, the outer lip often slightly indented, and some- 

 times sufficiently so to give the mouth a triangular outline. 



In exfoliated, weathered specimens, the cells are seen to be cylindrical and separately 

 walled, but closely in contact. The width of tbree of these cells occupies the space of one 

 tenth of an inch ; their length is about a third of an inch. No evidences of septa or la- 

 mellae can be detected. 



The cell-mouths of this abundant and beautiful species resemble Coenites, Alveolites, and 

 Cladopora. The fossil differs from Coenites and Cladopora in not having a solid coenencbyma, 

 and — at least from the usual forms — in its foliaceous ensemble. It differs from Alveolites in 

 the want of intra-cellular structure. Some species of Cladopora figured by Hall, however, 

 exhibit generic characters to which the present species is sufficiently conformable. 



Cladopora verticillata W. and M. 

 Plate II. figure 2. 



Corallum arising in the form of a stem, from which spreads out, horizontally, in all direc- 

 tions, a thin and delicate frond, composed of small radiating cells continually multiplying 

 in number with the distance from the axis. This circular frond is covered superiorly by 

 an epitheca through which the cell-mouths open as in other species. The mouths are tri- 

 angular-crescentic ; the cells show traces of dissepiments. At the height of an inch and a 

 half above the first frond is another, in all respects similar, and a cylindrical perforation 

 runs through the rock from one to the other. This structure has been seen in two unmis- 

 takable specimens. It seems probable that other verticils or circular fronds occur between 

 the two observed, and that the whole space was originally filled up with verticils of cells 

 alternating with plates of epitheca ; but of this we have no other evidence than the porous 

 condition of the rock, with occasional traces of minute coral tubes. 



In the specimen which is the subject of this description, a second stem, smaller than the 

 first, is seen perforating the rock for the depth of half an inch, and sending out a verticil 

 which becomes confluent with that of the larger specimen. Is this a new colony rooted, 

 banyan-like, from the branches of a parent ? 



The axis in our specimens is hollow. The filling is a calcareous clay, showing no other 

 structure than a slight porousness, with obscure vertical stria'tions on the exterior. We 



