297 



diaphragms. Mosoposes are ahnni1;iiit in tlic li:is;il iiortinn. (k'crcasiiig in 

 size and numbers in tlio poriplicial n";;iiin of iumIiuc spfcinicns. Tiicy arc 

 closely tabulated and bead-like. AeantlioiM>res are present, having a dis- 

 tinct lucid center (lumen). 



StrottKitotri/pa lamcUuta n. sp. Plate XI, Figs. 1-2. The zoariiuu consist 

 of superimposed layers varying from 1 to 2 mm. in thickness. The base is 

 covered with a \vriid<led e]>itlioca. The surface is even and without dis- 

 tinct maculae. 



The zoecia are large, 4 to 5 in 2 mm., irregular in size and shape. When 

 the mesopores separate the zoecia completely, they are oval or subcircular, 

 and where the mesoiwres are few or absent the zoeciiil tubes are elongate 

 polygons as seen in the tangential section. 



From 3 to 7 acanthopores surround each zoecia and inflect the walls. 

 They arise in the early mature zone, increase in size rapidly, and then taper 

 gradually to their extremity which projects above the zoiiidal cavity in 

 perfectly preserved specimens. 



The zooecial tubes are short and slightly inclined in the proximal region. 

 The diaphragms are few, varying from ..1 to 1 tube diameter apart. The 

 mesopores are more numerous in the basal zone than in the mature portion 

 and are crossed by relatively few and iri-egularly spaced diaphragms. 



This species differs from the laminated form in the Black Kiver of Min- 

 nesota in having less number of mesopores with fewer diaphragms ; more 

 angular zoecia and pronounced inflection of the zoecial walls by the well 

 developed and relatively thick-walled acanthopores. 



Occurrence : Pierce limestone, Murfreesboro, Tennessee. 

 Holotype : 44718, U. S. Nat. Mus. 



Stromatotrj/pa incrustans n. sp. Plate XI, Figs. 3-4. Zarium forms thin 

 incrustations (from .5 to 1 mm. in thickness) upon foreign bodies. The 

 surface is smootli and without maculae. 



The zoecia are subangular, relatively thick-walled for the genus ; G to 7 in 

 2 mm. Mesopores are few, occurring mostly at the junction angles of the 

 zoecial tubes. 



The acanthopores are aliout as numerous as the zoecia; of large size; 

 thin dark wall, and a large central lucid area. They originate near the 

 ba.se of the zoarium and extend to the surface as well developed structures. 

 In the zoecia there are three to four diaphragms, in the space of one tube 

 diameter, and about twice that many in the mesopores. 



The smaller size and thicker walls of the zoecia. the less numbers of 

 mesopores and larger and fewer ai:iiil Iioimucs scp.-iiatc this species from 

 Stnnnatotrypa lumclluta n. sp. 



Occurrence: Pierce limestone, at ford 1", mile southeast of lUackiiiMii. 

 Rutherford County, Tennessee. 



Holotype : 245 — 14. Indiana TTniversity. 



Sfromatotrypa rcgularis n. xp. Plate XI, Figs. 5-0. The zoarium con- 

 sists of thin layers uiwn foreign bodies, varying in thickness from .8 to 2 

 mm. The surface is even, and without monticules or maculae. 



