288 



phery, closing the mesopo.es a A rounding tlie apertures of the zooecia. 

 Two to three diaphragms occur in the zooecia of the mature zone in the dis- 

 tance of one-tube diameter. 



Many of the characters of H. palcru are very similar to H. nucrostifjma 

 from the Richmond, but the much less number of acanthopores and the 

 absence of inflections of the zooecial walls by the acanthopores in H. patera 

 serve to differentiate them. 



Occurrence : Pierce limestone : 2 miles northwest of Murfreesboro, Ten- 

 nessee, at Stokes Gannon's ford. 



Holotype : 242-4. Indiana University. 



Heterotrypa stonensis n. sp. Plate VIII, Figs. 1-2. Zoarium ramose ; 7 to 

 15 mm. in diameter. The surface is smooth ; monticules are absent ; small 

 inconspicuous maculae of clusters of large zooecia are numerous, .2 to .5 

 mm. across and 2 to 2.5 mm. apart, measured from center to center. 



The zooecia are thick-walled, and subcircular. A completely developed 

 cingulum is present in each zooecia. The true zooecial wall is angular, 

 finely granular, amalgamated and separated from the cingulum by a distinct 

 dark line of contact ; 8 to 9 zooecia occur in 2 mm. 



The acanthopores are of medium size, with indefinite boundary; 2 to 3 

 about each zooecia. The central lumen is very small and mostly indistinct. 



MesoiX)i'es are very few. being absent in most of the tangential sections. 



The zooecial tubes in the immature region are thin-walled and crossed 

 by very few diaphragms. They turn outward in a slight curve to the initial 

 mature region where the bending is subangular and short. Thruout the 

 deep mature zone the tubes proceed directly to the surface. 



Diaphragms in the mature region are spaced about one-fourth to one-half 

 tube diameter apart. Coalesced and infundibular diaphragms are present. 



The scarcity of diaphragms in the axial region, the thinner cingulum and 

 inconspicuousness and zooecial composition of the maculae of Heterotrypa 

 stonensis separates it from H. patera. 



The greater abundance of acanthopores, presence of numerous dia- 

 phragms in the axial region and the well developed maculae of H. micros- 

 tigma distinguish it from H stonensis. 



Occurrence : Pierce limestone ; two miles northwest of Murfreesboro, 

 Tenn., at Stokes Gannon's ford. 



Holotype : 242-5. Indiana University. 



Family Constellaridac. Uhich. 



The zooarium is ramose, frondescent, laminar or incrusting. The stellate 

 maculae is probably the most obvious character of this family ))ut greater 

 importance is assigned to the granular wall structure in the mature region, 

 and the pi-esence of hollow spines or granules which occur in the place of 

 true acanthopores. Mesopores are angular and usually abundant. 



Oenns Constellaria Dana. Genotype: Ceriopora constellata (Van Cleve, 

 M. S.), Dana. Constellaria Dana, Zoophyta, 184G, p. 537. Edward and 

 Haime, Mon. d. Polyp. Foss. d. Terr. Pal. (Arch. Mus. d'Hist. Nat, 5), 



