424 PALAEONTOLOGY OF ILLINOIS. 



the New York types of that species seemed to have been lost 

 sight of entirely. Several years ago having had an opportunity 

 of examining Hall's original specimens, together with another 

 set of authentic examples, I came to the conclusion that the 

 Cincinnati specimens belonged not only to another species, but 

 to a distinct genus as well. In 1848 Dana proposed the genus 

 Constellaria for the Cincinnati species, but failed to give it a 

 specific name, and, as I have said till recently, it has gone cur- 

 rent as either Constellaria or Stellipora antheloidea. In 1875, 

 Nicholson described and figured a closely allied but distinct 

 species under the name Constellaria polystomeUa\ . Examples of 

 this species are not uncommon at several localities in Ohio and 

 Indiana, where the upper layers of the Cincinnati group are 

 exposed. The species also occurs at an equivalent horizon in 

 Wisconsin and Illinois, but has not been found at Cincinnati. 

 As it differs both internally and externally from the Cincinnati 

 species, I could not accept Mr. Whitfield's proposition to apply 

 Nicholson's name to all the western^ forms, but considered my- 

 self justified in applying the new name florida to the common 

 Cincinnati species. 



The genus as defined by me includes at least five species and 

 several varieties, all of them from the Cincinnati rocks. What 

 may prove another species, closely allied to C. linntaris, occurs 

 at Wilmington^ 111. 



CONSTELLARIA PARVA Ulrich. 



PL XXXIV, Figs. 1-lb. 



Zoarium consisting of irregularly undulating small fronds, two 

 to three mm. in thickness, and twenty-five mm. or more in 

 height, growing from a broad basal expansion. Surface smooth, 

 showing small star-shaped maculae of the type characteristic of 

 the genus, varying from one to one and one-half mm. apart, 

 measuring from center to center, and averaging sixty in the 

 space of ten mm. square. Zooecial walls comparatively thin 

 throughout, though ring-like in the mature region. Zooecial 



tPal. Ohio, Vol. II. p. 215. 



tGeol. of Wis., Vol. IV, p. 251, 1882. 



