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NOTE.—After this paper had been put in type, I learned that Dr Forster, of 
the University of Vienna, was going to publish very shortly the results of his 
long studies of the temperature of the rivers of Central Europe. Dr Forster’s 
previous publication had been known to me only through a short paragraph 
in Nature. But as I am a more recent student of these matters, I will- 
ingly allow him full priority; and whilst claiming complete independence 
and originality for myself in all advanced in this paper, I regard Dr Forster 
as the first to treat systematically this important problem, 
XXIL A. still further Contribution to our Knowledge of 
Palzeospondylus Gunni, Zraquair. By R. H. Traguatr, 
Esq., M.D., LL.D., F.R.S. [Plate LX.] 
(Read 20th December 1893. ) 
At the conclusion of my last paper on Palwospondylus 
(1), I expressed a hope that additional material might soon 
turn up to “throw still more light upon the structure of this 
strange relic of early vertebrate life.” 
My hopes have so far been realised, inasmuch as among 
the numerous specimens which I obtained during my visit to 
Achanarras in August last, there are several which completely 
alter one’s idea of the configuration of the front of the head, 
besides explaining some very obscure appearances in that 
region in some of my previously-collected examples. From 
Mr D. Calder of Thurso I also obtained some additional 
