2M THE CANADIAN NATURALIST. [Yol. vii. 



6. Z. Hecuba. — Corallum large, expanding to a diameter of 

 2-i- inches in a length of 4 inches. Surface with numerous, 

 slightly elevated, rings of growth. Costal strias at the margin 

 of the calice about 1 line wide ; 5 or 6 in a width of 3 linea at 



• the base. Where the diameter is 28 lines, there are 50 laruj^ 

 septa, many of which reach the centre. Between these there are 

 50 smaller septa of about ] line in depth. The calice in a speci- 

 men 5^ inches in length, measured alons; the convex curve, is 20 

 lines deep. The wall is very thin, all the septa reaching the 

 margin, on approaching which, they all become of nearly the 

 same size, and reduced to thin elevated ridges, le.ss than a line 

 in heighth, with concave o-rooves between them. The bottom 

 of the cup occupies about half the whole width, nearly flat, the 

 septa forming small elevated lines upon its surface, converging to 

 the centre. The fossette is large and has three septa in it ; one 

 large and two small. This species resembles the last, but differs 

 therefrom in being a larger form, with the rudimentary septa 

 less developed. There is also a strong likeness between it and 

 Z. Stokesi. Coruiferous. 



7. Z. Egeria. — Corallum, often strongly curved for 2 or 3 

 inches at the base, becoming more nearly gtraight above ; expand- 

 ing to a width of from 18 to 26 lines in a lensrth of 4 or 5 inches. 

 Surface with numerous rings, and a few undulations of growth. 

 Epitheca thin, with 8 or 10 costal striae in a width of 3 lines 

 near the base ; about half that number in the same space in the 

 upper part of the coral. 



In one specimen, in a transverse polished section, 3 inches 

 from the base; there are 64 large septa 3 or four lines in depth, 

 ;and the same number of small ones between 1 and 2 lines in 

 depth. The diameter of the coral is here 18 lines. 



In another individual, there is the same number of septa as in 

 the former, the larger 5 or 6 lines in depth and the smaller from 

 2 to 4 lines. The diameter of this section is 25 lines and was 

 cut across the coral at 4^ inches from the base. 



A silicified specimen. 6 inches in length, shows that the cup is 

 over an inch in depth, and the tabulae excessively thin and fra- 



-gile. 



This is a more slender species than Z. Hecuha. It differs 

 further in having more numerous septa at the same diameter and 

 the large ones not reaching the centre excapt apparently near the 

 /base. It occurs in the Corniferoug. 



