136 



Fig. 19. Trackypora limbata. Branch nat- 

 ural size, and a portion enlarged to show the 

 calices (after Hall j. 



TRACHYPORA LI M I! ATA . 



I Eaton.) ( Fig. 19.) (111. 

 Dev. Fobs., PI. XXXIII. 

 Striatopora limbata. ) 



Distinguishing ( 'h a ra c - 

 ters. — 11 atlier irregularly 

 disposed oval calices: mod- 

 erately strong peristomes, 

 with radiating ridges run- 

 ning out upon the thickened 

 walls; corallites abruptly 

 bent outwards. 



Found on the " ... 

 south Shore of Lake Erie, 

 near Eighteen Mile Creek.'' 

 ( Eaton, Geol. Text-book. p. 

 39.) Common at Morse 

 Creek. 



Genus MONOTRYPA. Xicholsox. 



[Ety. : Monos, one ; trypa, hole.] 

 (1879 : Nicholson, Tabulate Corals of the Paleozoic Period, p. 293.) 



Corallum composed of long, slender, prismatic corallites, 

 which are of two kinds, not conspicuously different from each 

 other. The large tubes are aggregated into clusters or 

 ''monticules,'' and very slightly differ in size from the 

 smaller ones. The smaller tubes occupy all the spaces be- 

 tween the monticules. All the corallites of both kinds are 

 thin-walled, regularly polygon;! 1, and similarly tabulate, 

 the tabulae being remote and few in number, and not 

 uncommonly disposed at corresponding levels in contig- 

 uous tubes. 



MONOTKYPA FRUTICOSA. (Hall.) (Fig. 20.) ( ( 'h;rt t'tes 



fruticosus. Hall. 111. Dev. Foss.. PL XXXVIII.) 



Distinguishing Characters. — Tubes passing upwards and 

 gently bending outwards from a central imaginary axis; 

 numerous small, low, monticules, scattered over the surface 



