PALEONTOLOGIC CONTRIBUTIONS 23 



by smooth smaller bands. These intervening bands bifurcate at the 

 boundaries of the second and third cycles. The radial bands bear a 

 regular succession of horizontal rows of pores, the whole suggesting 

 ambulacral areas. The other side, which was considered the under- 

 side, shows only irregularly radial folds and wrinkles. 



It is stated in the description that no trace of the substance of 

 plates was found ; in fact there is no trace of the original substance 

 of the bodies preserved, only the casts of the exterior surface, which 

 are separated by sandy matrices. 



Some years after the publication of the description of the prob- 

 lematicum, an interesting note by Theodor Fuchs : Ueber Parop- 

 sonema cryptophysa 1 und deren Stellung im System, was printed in 

 the Centralblatt fur Mineralogie, etc., Jahrg. 1905, no. 12, p. 357. 

 The well-known Austrian paleontologist offers the interesting sug- 

 gestion that Paropsonema may have been the float or pneumatophOre 

 of a siphonophore related to Porpita. He writes : " Porpita, 

 which is found floating in all warm seas on the surface and some- 

 times appears in immense multitudes in the gulf stream, consists 

 generally of a flat gelatinous or chitinous disk, which serves as 

 float, and to the underside of which the various types of polyps 

 are attached, of which the colony consists." 



In Agassiz's paper on the Porpitidae and Velellidae (Mem. Mus. 

 Comp. Zool., v. 8, pt 2, 1883), is given the following brief descrip- 

 tion of the float of Porpita : 



If one views the float of a Porpita from above, one sees a large 

 number of concentric circles, which are crossed by a system of 

 radial lines, which with the concentric circles produce a most 

 regular meshwork. In studying the interior structure of the disk, 

 one finds it to present a great similarity to the structure of an 

 orbitolid foraminifer. One finds a central sphaeroidal chamber, 

 surrounded by eight wedge-shaped chambers. These are sur- 

 rounded by smaller chambers, arranged strictly geometrically in 

 numerous concentric circles. The chambers, which belong to the 

 same cycle, are completely shut off from the adjoining cycles, but 

 connected with each other, since the lateral partitions are not 

 complete, but only in the form of projecting folds. 



All these chambers contain air and are connected with the atmos- 

 phere by fine pores that on the surface are arranged in radial rows. 

 Since every pore is situated on a ridgelike prominence of the disk, 

 radial ridges with pores are formed on the surface. 



If one views the underside of the disk, one finds a large number 

 of radially arranged, well-shaped folds, which increase in number 

 toward the periphery through fission or intercalation of new folds 

 and which carry the various single polyps. 



1 Misprint for cryptophya. 



