1865.] BILLINGS— PALAEOZOIC FOSSILS. 427 



developed, but they can be distinctly seen in the inside of the cup 

 as so many small vertical ridges ; there appear to be twelve of 

 them. The tabulae are somewhat irregular, being either horizon- 

 tal, oblique, flat, convex or concave, from two to four in one line, 

 The coenenchyma is composed of small vesicular cells from one- 

 sixth to one-third of a line in diameter. The surface between the 

 cells is, when perfectly preserved, covered with small rough tuber- 

 cles. "When the specimens are worn, the surface presents only the 

 circular apertures of the cells and is destitute of granulation. 



Only six specimens of this species were collected, and they are 

 all of the clavato-turbinate form. It is possible that hemispherical 

 or globular colonies may exist as there is much variety in the form 

 in species of this genus. Some of the cells are nearly two lines in 

 diameter, others less than one line. 



By the size of the cells this species is distinguished from all 

 others of the genus except H. megastoma (McCoy) and H. macros- 

 tylus (Hall). From these it differs in the structure of the tissue 

 between the tubes. In II. megastoma the cells of the coenenchyma 

 are arranged in polygonal columns. Such, also, seems to be their 

 structure in H. macrostylus. The species which Edwards and 

 Haime have placed in their genus Lyellia, L. Americana and L. 

 glabra, have the tubes rather more widely separated and the septa 

 more strongly developed. Occurs at Junction Cliff, Anticosti ; 

 Division 1 ; Anticosti group ; Middle Silurian. T. C. Weston. 



H. affinis.— Corallum hemispheric, globular, pyriform, clavato- 

 turbinate or tuberose, sometimes incrusting other fossils in a thin 

 layer ; cells usually circular, often sub-polygonal, in contact with 

 each other or barely separate, from half a-line to little less than one 

 line in diameter, the more common width being about two-thirds 

 of a line, their margins thin, distinctly elevated above the general 

 surface, and, in perfect specimens, crenulated or serrated with 

 twelve small, rough, pointed tubercles. Septa rudimentary, rarely 

 visible but in certain conditions of preservation distinctly striating 

 the inside of the cells and tubes below. The tabulae are usually 

 horizontal, three or four in one line. Owing to the close arrange- 

 ment of the tubes there is very little coenenchyma, and this is vesi- 

 cular. 



When the cells are closely crowded together they become more 

 or less prismatic with polygonal apertures, and, it is then difficult 

 to distinguish the specimens from certain species of Favosites. In 

 general, however, they are circular although in contact or nearly 



