AKT. 13 A I!fEW LOWER CAMBE{IAN HYDROZOAN RUEDEMANN 5 



CAMPTOSTROMA,= new genus 



Lenticular or spheroidal bodies with chitinous or slightly calcare- 

 ous skeleton present in only one surficial layer. One (upper?) 

 surface has central circular area with granular surface, and short, 

 subcircular, zooidal tubes, surrounded by primitive astrorhizae. 

 Central area surrounded by a concentric ring of radiating ribs with 

 granular surface. Remaining surface composed of reticulate mesh- 

 work of platelike spicules surrounding round pores and larger 

 monticules, with central groups of pores and knobs. 



Genotype. — C aniptostroTna roddyi^ new species. 



CAMPTOSTROMA RODDYI, new species 



Figures 1, 2 ; Plates 1-4 



D esciiption.— Hydiosorao. free, lenticular to ellipsoidal or sphe- 

 roidal in shape, of size of a small apple (largest, diameter 66.5 mm; 



Figure 1. — Diagranimatic cross section of the holotype of 

 Camptostroma roddyi, showing fold on both the upper 

 and under sides produced by lateral compression 



another, incomplete, 45 mm), flexible, probably floating. One side 

 (upper?) possessing a central, circular to elliptic, slightly convex 

 area (33 by 28 mm in type), with depressed center; its surface is 

 granular and perforated by fairly evenly distributed (in quincuncial 



Figure 2. — Vertical section of Camptostroma roddyi, showing the 

 layer of coeiienchym with the thecal pores on upper and under 

 sides and monticules on underside. The dotted lines indicate extent 

 of ribs 



arrangement) subcircular depressions (many of which have a limo- 

 nite nodule at the bottom and originally were undoubtedly pores), 

 about 0.5 mm in diameter and 1.5 mm apart. Many of the pores 

 surrounded by somewhat crudely radiate or stellate furrows, suggest- 

 ing a primitive form of astrorhizae of the Tubulariae (as P&ro- 

 sphaera) and Stromatoporoidea. 



2 Ka/nrror, flexible + arpufia, layer. 



