264 REPORTS ON THE STATE OF SCIENCE, ETC. 
the other on the goniatites,’ is recognised, but the Report certainly does not make clear 
the necessity for the use of a separate series of symbols for time-divisions in the gonia- 
tite sequence. We feel that there is a subcurrent of opinion running throughout 
workers on the coral-brachiopod phase that the major divisions of that phase should be 
used as time-divisions in the division of the Culm. For instance, the suggestion is 
made that ‘D3,’ should indicate a goniatite phase of ‘D,’ age. Such a term no 
doubt would be useful to workers on the Yoredale beds, but it has little significance 
when applied to theCulm. The division next above ‘ D;,’ namely ‘ O,’ would obviously 
be hopeless as a time-division of the Culm, and even in the typical Yoredalian no real 
attempt has as yet been made to define its boundaries in faunal terms. 
The Culm phase which had been long dominant in Germany and parts of England 
(Devon and Craven) became far more widespread in the famous Posidonomya zone, 
now defined in terms of its goniatite succession and, following Vaughan and Matley, 
designated shortly as ‘ P.’? By this symbol it is now well known to geologists both in 
the Old and New Worlds. We greatly regret, therefore, that certain workers on the 
corals and brachiopods should deprecate the use of this term as a time-division. As 
far as they are concerned, restricted as their activities are to those narrow areas in 
which corals existed up to the end of the Lower Carboniferous, undoubtedly the 
term is unnecessary and need not be used, but to the ever-increasing number of 
workers on the great Culm phase, both in these islands and abroad, the symbol 
connotes a very definite faunal division, and we feel that any attempt to cast doubt 
on the propriety of its use is ill-advised. We feel therefore that the Committee 
ought to accept the definition of ‘P’ in terms of the goniatite fauna given in the 
Proc. Y.G.S8., vol. xx., pt. I., 1924, and recommend its use to workers. 
Having very strongly expressed our views to the effect that we considered all 
correlation to be outside the function of this Committee, we have finally agreed, on the 
advice of the Chairman, to the introduction of certain tables which might lead to 
clearness in following the Report. We think, however, that to lead readers to regard 
them as in any way backed by the authority of the Committee would be undesirable, 
since correlation can only be based upon an appeal to faunas, and the faunas are only 
very partially and inadequately stated in the tables. 
We have urged upon the Committee the desirability of defining the zones in terms 
of faunal lists included in the Report, and were prepared to supply such lists for the 
Culm phase. We understand, however, that there are difficulties in the way of this 
procedure in the case of the coral-brachiopod phase, the faunas being either too ill- 
defined or composed of undescribed forms. Such clear-cut definition would have 
aided greatly in the comparison of the two phases and in the interpretation of mixed 
phases. The absence of such definitions in the coral-brachiopod phase was largely the 
cause of the confusion which this Committee was set up to rectify, and if confusion is 
to be avoided in the future, in our opinion much greater precision in the definition of 
coral zones will be required. 
Parthenogenesis.—Report of Committee (Prof. A. MrEx, Chairman ; 
Mr. A. D. Peacock, Secretary; Dr. J. W. Hzstor Harrison and 
Mr. R. BaGnatt.) 
FurRTHER work on parthenogenesis in saw-flies and moths is reported as follows : 
The species Thrinaz miata, K1.,and Thrinax macula, K).—To throw light on various 
aspects of sex and parthenogenesis, preliminary attempts have been made to cross 
these two species, but, so far, without success. The amount of macula material has 
been smaller than anticipated owing to heavy parasitisation, but the experiments 
do seem to indicate that hybridisation can be induced. 
Incidentally, further morphological and biological observations have been made. 
The former comprise detailed studies of the larva of mixta, the adult macula and the 
external and internal genitalia of mixta; the latter relate to the burrowing habits of 
mixta, sex ratio in mixta, and parasitism by ichneumons. 
Papers on the above are in preparation. 
Continuous thelytokous parthenogenetic reproduction in Allantus (Hmphytus) pallipes, 
Spin., and Pristiphora pallipes, Lep.—This is the fifth consecutive season for partheno- 
genetic strains of these species. Strains of the former have reproduced for nine 
successive generations, and of the latter for thirteen, without resort to sexual methods. 
