102 ON THE FOSSII/ CORALS aF THE 



demonstrates to us the very weighty fact that in Europe F. Gothland" 

 ica is found to be variable in the eharactex that is most generally reliecl 

 upon as a means of identifying the species. 



In order to ascertain whether or not our Canadian forms could be 

 divided into several species, I undertook to write out a detailed des- 

 cription of each specimen in the large collection of the Geological 

 Survey, noting the following characteristics: — 1st, the diameter of the 

 tubes. 2nd, the form of the diaphragm, and their structure, whetheir 

 complete or incomplete. 3rd, the presence or absence of the spiniform 

 tubercles. 4th, the number of rows of pores. 5th, the distance of 

 the pores from each other. 6th, the presence or absence of the elevated 

 border around the pores. 7th5 the presence or absence of longitudinal 

 lines or strise on the faces of the tubes. The specimens were from 

 Anticosti, Cape Gaspe, the coast of the Bay of Chaleurs, the Eastern 

 Townships, the head of Lake Temiscamangue, the Niagara ridge, 

 Drummond Island, and various localities of Devonian rocks in Canada 

 "West. It would be too much to give even a small portion of the 

 details in this paper, and I shall therefore state briefly the principal 

 results. 



] St. The size of the tubes in all those specimens which have the 

 internal characters of J'. GotJdmidica is variable, and ranges from 

 three fourths of a line to a little more than two lines. 



2nd. The greater number have the tubes between one line and one 

 line and a half in width. 



3rd. There are more specimens above one line and a half in the' 

 "Devonian than in the Silurian. 



4th. The diaphragms may be complete or incomplete in the same 

 i^^specimen, or in different parts of the same tube. This character is 

 more common in Devonian than in Silurian specimens, and more so in 

 ;the lower than the upper Silurian. 



5th. The spiniform rays exist in both upper Silurian and Devonian 

 specimens, but have not been observed in the lovrer Silurian. 



6th. The pores are usually in two series, but specimens with one, 

 two, or three rows, are not uncommon in both the upper Silurian and 

 Devonian rocks. I have seen no pores in the lower Silurian specimens. 



7th. The elevated border around the pores occurs in both Silurian 

 and Devonian forms, and in the same specimen may be absent from 

 -one part and present in another. 



