356 SECTIONAL TRANSACTIONS.—J, K. 
The fixed individual valuation supposed to be operative in individual exchange seems 
also to be a psychological fiction. 
A conception of individual valuation consistent with the actual complexity of 
the psychological relationship between buyer and seller is one which would regard 
the individual valuations not as a single price at which the individual concerned will 
be willing to complete his share of the transaction, but as a whole class of possible 
prices between which the probability of him completing his share of the transaction 
ranges from zero to one. 
17. Mr. H. E. O. James.—Regularity and Rhythmicalness. 
An attempt was made to investigate the connection between rhythmicalness and 
regularity, chiefly in regard to temporal regularity in auditory and ‘ motor ’ (muscular) 
rhythmical series. Controlled irregularities were introduced into otherwise regular 
series of auditory stimuli producing rhythm, and statements were called for from 
listeners in regard to the effect of these irregularities upon the rhythmicalness of the 
series. In the case of motor series a less direct method had to be adopted. The 
subjects were asked to state which of two consecutive motor series performed by them 
was the more rhythmical. The temporal irregularity of the recorded movements of 
the compared series was then measured in order to ascertain whether or not the more 
rhythmical of the pair of composed series, as stated by the subject, was the less 
irregular. 
By such methods it was found in regard to both auditory and motor series that 
the rhythmicalness of a series varies, on the whole, directly with the temporal regularity 
of the series. It was possible to show in the case of auditory series that other sorts of 
regularity are also conditions of rhythmicalness. These various kinds of regularity 
can be collectively described as ‘regularity of pattern.’ The concept of pattern- 
dispositions seems useful in accounting for certain phenomena of rhythm, not only 
phenomena directly related to regularity, but also phenomena of ‘ perseveration ’ and 
preference. 
SECTION K.—BOTANY. 
(For references to the publication elsewhere of communications entered in the 
following list of transactions, see page 592.) 
Thursday, August 27. 
Mornine. 
1. Presidential Address by Pror. J. Luoyp Witttams on The 
Phaeophyceae and their Problems. (See page 182.) 
2. Prof. F. O. Bower, F.R.S.—A Phyletic Grouping of the Filicales. 
Having made a prolonged study of the Filicales and compared them according to 
twelve distinct criteria, relating chiefly to the sporophyte, but also in less degree to 
the gametophyte ; and having checked the results by reference to the observed sequence 
of related fossils, it is now possible to arrange the class so as to represent what are 
believed to be their natural affinities. No attempt is made to connect them into a 
phyletic tree. All that is intended is to place the several families in graphically 
indicated relations, which express the leading results of comparison. The ferns 
believed to be the most primitive are placed at the base of the scheme; and suc- 
cessively those that are more advanced stand higher in the scheme, the succession 
being from the Simplices to the Gradate and Mixte. To the left are placed those 
ferns which have, and retain most fully, the marginal position of the sorus, a feature 
which is characteristic of most relatively primitive types; while those which have a 
superficial position of their sori are disposed towards the right. 
Two important lines, the one marginal the other superficial, appear as the modern 
Schizeacess and the Gleicheniacee. In close relation with the former are the 
Hymenophyllacee, Loxsomacex, and Dicksoniacez, which are all marginal. With 
the superficial Gleicheniaces are ranked the Matoniacee and Dipteridaceex, while the 
