ir. /. Robinson — Paleozoic Alcyonarian, Tumularia. 163 



Family Heliolitidas 

 Genus Tumularia, noni. nov. 



1859 Cohtnmaria (partim) Billings. Can. Nat. Geo!., vol. iv, 428. 

 1806 Stylarcea Seebaeli. Zeit. deutsch. geol. Ges., vol. xviii, 306. 



1878 Stylarcea Nicholson and Eiheridge. Mon. Sil. Foss. Gir- 



Van Dist., GO. 



1879 Stylarcea Zittel. Ilandb. d. Pal., vol. i, 239. 



1883 Stylarcea Roemer. Leth. Geog., Pt. I, Leth. Pal., 456. 

 1899 Stylarcea Lindstrom. K. Svenska Yetens.-Akad. Hand- 



lingar, vol. xxxii, 110. 

 1S99 Stylarcea Larabe. Cont. Can. Pal., vol. iv, Part I, 91. 



A free translation of the original generic description is as 

 follows : 



Vermicular, perforate sclerenehyuja forming encrusting 

 masses surrounded by a thin epitheca. Cells polygonal ; 

 moderately deep, with a strongly developed spongy columella. 

 Walls massive. Spines occur at the corners of the cells. Septa 

 strongly crenulated ; descending abruptly to the calyx floor. 



A summary of the genera Protarcea and Styla-rasa {= Tu- 

 mularia) was given by Larhbe,* who described and figured as 

 Protarma vetusta a form which differs from other figures and 

 descriptions of that species. The form described by him dif- 

 fers from Protarma in that it has a parietal or pseudo- 

 columella, the calices are far apart, and there are small tubules 

 in the intervening areas. It varies from Tumularia in that it 

 has twelve septa while Tumularia has but eight, or rarely 

 sixteen ; it has tubules between the calices while Tumularia 

 has not; the columella is parietal, that of Tumularia is 

 essential. 



Excluding this form because of the differences mentioned, 

 Protarma is clearly distinct from Tumularia. The original 

 description of Prolarwa is not definitive, but the genus was 

 redescribed by Nicholsonf as follows : 



" Corallum forming thin crusts, about one-third of a line in 

 thickness, which grow parasitically upon foreign bodies. Calices 

 nearly equally developed, usually hexagonal, about one line in 

 diameter or rather less, shallow, the bottom of the cup. being 

 tuberculated. Septa twelve in number, sub-equal, extending 

 but a short distance inwards towards the center of the visceral 

 chamber. Walls of the calices thick." 



The points of distinction upon which is based the retention 

 of Tumularia as a distinct genus are : 



1. Eight or sixteen septa; Protarcea has twelve. 



2. An essential columella ; Protarcea has a parietal columella 

 or none at all. 



* Cout. ,Can. Pal., vol. iv, Part I, p. 89. \ Pal. Ohio, vol. ii, p. 221. 



