182 DUBLIN NATUKA.L HISTORY SOCIETT. 



the plant is said to have occurre(f in Norway, therefore it could not be 

 a southern form. Surely the gentleman who made that remark had 

 forgotten the southern shells found in that country, and in the seas much 

 farther north, and which are, nevertheless, considered as southern types 

 by some of our greatest and most philosophic naturalists. 



He next would allude to some of the arguments brought forward 

 by Professor Harvey ; and Dr. Kinahan felt much difficulty, because it 

 might be thought to be presumption in him to venture to express an 

 opinion contrary to an authority deservedly of so high a reputation ; but 

 it appeared to him that one of the arguments brought forward in reply to 

 Mr. Andrews was really of no weight in this case. The case of Parkeria 

 quoted merely showed that even such a great botanist as Sir "W. J. 

 Hooker may attach too great value to a single trivial character. Every 

 one who has studied the ferns living must know, that of all the charac- 

 ters selected as specific and generic, the least valuable and most uncer- 

 tain are those derived from the form, presence, and position of the trans- 

 verso ring. Indeed, he almost questioned the utility of the characters at 

 all. The example quoted, besides, was an instance of what was already 

 stated, viz., the value of cultivation in showing the distinctness or iden- 

 tity of two plants. 



The change in the position of the sori of Scolopendrium had been 

 quoted ; Professor Kinahan had himself, as the records of the Society 

 show, exhibited to the members specimens in which the sori were partly 

 on the dorsal, partly on the frontal aspect of the frond ; but even in these 

 the variations were more seeming than real, the relations between the 

 woody bundles of the plant and the sori remaining constant, even in the 

 most monstrous specimens. The argument drawn from the presence of 

 both ferns in almost every locality where one occurs has been already 

 shown to be an argument in favour of their distinctness. It is incon- 

 ceivable that the same modifying causes could exist in all the counties 

 in which these ferns are found. So that it appeared that, of the argu- 

 ments adduced to prove the inconstancy of the fructification, one only 

 exists, — a change in an organ of very minor importance. One statement 

 of Dr. Kinahan's on the former night had been totally misunderstood, 

 viz., the value of foreign travel. What he said was, *' that if, because 

 in the course of travel we find gradation al forms between what were 

 considered species, that therefore we are justified in uniting in one the 

 extreme species connected with that gradational form ; and the only 

 result we would attain from such travel woujd be the reduction of nearly 

 every known species to one, and that to include these forms our definitions 

 of species would finally come to be generic, and not specific." One other 

 argument, or rather statement, seemed scarcely to need notice, viz., that 

 if in these species fructification was the most striking and constant dia- 

 gnostic character, that therefore it was the only character, and also dia- 

 gnostic all through the forms. Just as well might we argue, that because 

 certain colours and markings are diagnostic of species in some birds, that 

 therefore colour must have equal value among all birds — a statement 



