301 



The zooecia are elliptical. In the central portion of the lateral surface 

 tlicy are arranged in longitudinal and diagonal rows (7 to 11 in the type 

 specimen), with the lojiger diameters of the apertures parallel to the mar- 

 gins. Between the longitudinal series and the edges of the branch occur 

 short, less definite series, each consisting of 4 or 5 zooecia that extend ui>- 

 ward and outward. The longer diameters of these zooecia are parallel to 

 \he longitudinal series of apertures in the proximate branches rising from 

 liie coiTesponding margin. 



Close set, wavy rows of tubnli are present upon the crest of the ridge 

 separating the series of zooecia, and in a few cases a single one is found 

 between the zooecia within the .<-eries. In the subsolid areas their distribu- 

 tion shows much less systematic arrangement. 



The longitudinal .section shows clearly the bifoliate character of the 

 zoarium and the presence of median tubuli. The primitive zooecial tul)e is 

 .3 mm. long, lies inclined uiwii the median lamina, extends upward, in- 

 creases in size with age and ends abruptly by a short turn into the long 

 (.7 to .8 mm.) vestibule. No superior septum is developed. From one to 

 four diaphragms cross some of the vestibular tubes. The intercellular space 

 in the vestibule zone consists of solid tissue except In a few cases near the 

 junction of the vestibule and the primitive zooecia, where diaphragm-like 

 structures occur. 



This species resembles RMnidictya mutabilis in many of its characters, 

 but differs in the presence of diaphragms in the vestibular tubes. 



Occurrence : Pierce limestone, Murfreesboro, Tennessee. 



Holotype: (98) U. S. Nat. Mus. 



Khinidictya salemcnsis n. sp. Plate XIII, Figs. 4-5. The zoarium consists 

 of bifoliate branches 2 mm. thick and from 5 to 10 mm. wide. The surface 

 is even with small, solid, unequally distributed maculae, composed of com- 

 pact sclerenchyma and radiating rows of vertical tubuli. 



The zoocial apertures are small, oval, and separated from one another 

 by walls that are greater than twice the short diameter of the opening in 

 thickness and traversed by a single row or an irregular band of vertical 

 tubuli. The zooecia are not arranged in definite longitudinal series as in 

 many Rhinidictya : 7 to S occur in 2 mm. 



Median tubuli are shown in the longitudinal section. The zooecial tubes 

 lie along the median laminae for only .1 to .2 mm. and then turn outward 

 with a short bend and proceed nearly direct to the periphery. The inter- 

 spaces in the vestibular zone are filled with solid tissue traversed with num- 

 erous tubuli. No diaphragms occur in the zoocial tubes. 



Occurrence: Ridley limestone, 2i/i miles northwest of Salem. Ruther- 

 ford County, Tennessee. 



Holotype: 245-7. Indiana Cniversity. 



Rhittidictiia Irhanoncnsis n. sp. Plate XIII, Fig.s. G-7. The zoarium 

 liranches dichotomously. The branches are small. 2 to 2.2 mm. wide and 

 .."> nun. thick. The margins are celluliferous ; the zooecia in the rows near- 

 est the margin are more widely spaced than in the other series. Nine to 

 ten rows of zooecia are present on the lateral surfaces. 



