Knowlton — Problematic Organism from the Devonian. 207 



These problematic organisms which have been excluded from 

 the Characese, Foraminifera, and the calcareous Algae, were 

 described and exhibited informally to several members of the 

 Washington Biological Society, in the hope that some one 

 might be able to suggest a possible relationship. Dr. Th. Gill 

 suggested their resemblance to certain ova-capsules of Mollusks 

 and Hyclroida. Dr. W. H. Dall, to whom they were shown, 

 was also at first struck by the resemblance between these or- 

 ganisms and the ova-capsules of Mollusks, but after a careful 

 examination concluded that they could not possibly belong to 

 them as the shell of the organism is very thick and calcareous 

 while the ova capsules of the Mollusks are uniformly thinner 

 and not calcareous, but chitinous, which would not be likely to 

 be changed in fossilization. Mr. Richard Rathbun, of the U. 

 S. Fish Commission, also denied the possibility of their being 

 eggs or ova-capsules of star-fish. 



As to their resemblance to the gonangia of the Hydroida, an 

 examination of the Monographs by Allman in the Challenger 

 Reports shows it to be impossible. One of the species most 

 resembling it is Calamphora parvula AIL* ; but the gonangia 

 stand upon well marked stalks and they are described as "dis- 

 tinctly annulated " while these organisms are no less distinctly 

 spiral, and without positive evidence of a stalk or pedicel. 



The only other point which it now remains to consider in 

 this connection is the result of the observations made by Pro- 

 fessor W. C. Williamson and recorded in number X of his in- 

 valuable memoirs " On the Organization of the Fossil Plants 

 of the Coal Measures." Having formerly shown that one of 

 the supposed Carboniferous Foraminifera was really a plant he 

 has been lead to examine several other Carboniferous forms, 

 thinking it probable that some of them might also be proven 

 to be vegetable and not animal. The organisms investigated 

 by Professor Williamson were mentioned by Professor Judd 

 before the Geological Society of Londonf. He regarded them 

 as undoubted Radiolarians. They come from the limestone 

 rock near Rhydymwyn which is near Mold, in Flintshire. It 

 was impossible to separate the organisms from the matrix 

 and the only means of studying them was by thin sections. 

 They are shown to be hollow spheres, " most of which are fur- 

 nished with varying forms of peripheral appendages." Several 

 forms are named by Williamson, in some of which the wall of 

 the sphere is structureless, while in others it is described as 

 " double, but the inner and outer layers enclose between them 

 numerous small cubical compartments separated by radiating 

 partitions. The compartments are filled, like the central sphere 



* Challenger Reports, vol. xxiii., PI. x, fig. Ha. 



f Quart. Jourti. Geol. Soc, vol. xxxiii, Lond. 1877, p. 835. 



