PaIcoulolofi;y of the Ciuciuuati Group. 49 



at the ends of the branches. The single genus and species 

 referred to tlie order here, is problematical. Dr. J. S. New- 

 berry considers it to be doubtfully organic* 



Protostigm.v Lesqucreux, Am. Phil. Soc, Proc, vol. 17, 

 1877, p. 169. 



Cylindrical stems with rhonil)oidal scars. Only a single 

 species known from this horizon. 



P. SiGii.L.VRioiDKvS Lesqx. Ibid, p. 169. 



Branches or stems cylindrical, scarcely flattened by com- 

 pression ; surface marked by rhomboidal cicatrices, enlarged 

 on the sides, contiguous and in spiral order, with indistinct 

 impressions of oval, vascular scars in the center. 



(Consult on this species and on land plants in the Silurian 

 in general, Dr. J. S. Newberry, as noted above.) 



PROTOZOA. 



Animals generally of minute size, composed of a nearl}* 

 structureless jelly-like substance, (sarcode), showing no com- 

 position out of definite parts or segments, having no body- 

 cavity, presenting no traces of a nervous system, and having 

 either no differentiated alimentary apparatus, or but a very 

 rudimentar}- one.t 



Though abundant and of varied form in a living state, 

 species of this group are rare in the older rocks, becoming 

 more numerous, however, as modern times are reached. 

 Though mostly microscopic, some form large communities, 

 and are then readily perceived as a mass, though the individ- 

 uals remain minute. Several orders are knowai in both a 

 fossil and a recent .state. Only two of them, Foraminifera 

 and Spongida, are known from the Cincinnati group, if we 

 except an anomalous order, Stromatoporoidea, the position 

 of which is still a matter of discussion. 



Order Foraminifera. 



Structureless, gelatinous, generally minute animals, encased 

 in a calcareous shell, and frequently of considerable size in a 

 fossil state. The .shell divided into compartments, the walls 



* Am. Jour. Sci., 3d ser., vol. 8, 1874, pp. iio-i 13. 

 t Nicholson's Zoology, p. 44 



