SECTIONAL TRANSACTIONS.—D. cg 
and herring shoals. The life history of Calanus is complex, and length of 
life of various stages still open to doubt. 
Important above all is the movement of the swarms of Calanus, for they 
are far from being regularly distributed in the sea and depend for their 
movements upon currents of the ocean. It is now established that there is 
a spring influx of Calanus into the North Sea and a small winter population 
in that area. Data give some idea of the intensity of the influx (1933 data 
from Explorer). 
In spite of the small size of this animal some idea of its importance as 
food may be gathered when it is realised that the oil available from these 
crustacea alone in the N.E. Atlantic in spring would, if it could all be col- 
lected, have to be reckoned in millions of tons weight per month. 
Friday, September 7. 
Prof. J. VersLuys.—The distribution of marine animals and the history of 
the continents (10.0). 
If, trying to reconstruct the history of the continents, we look for indica- 
tions given by the distribution of marine animals, we must consider such 
groups as can be presumed to be conservative in their distribution. This con- 
servatism may be expected when the means of distribution are very limited, 
as in deep-sea corals, for instance, in the family of Primnoids, Gorgonacea, 
living on the continental slope. A southern fauna of Primnoids may 
clearly be distinguished from a circumtropical one, and the mixing is very 
limited, though the oceans are now in open communication, with continuous 
coastlines. This is in accordance with Wegener’s theory, that presumes 
the southern Atlantic to be of rather recent origin. 
The southern fauna is found on the coastal slope of the southern part 
of South America, on the southern coast of Australia and near some inter- 
mediate islands—but not on the coast of South Africa. This is not in 
accordance with present conditions, but again fits in with Wegener’s theory. 
Wegener assumes that Australia and South America were formerly lying 
much closer together as parts of one continent. The present distribution 
of southern forms on so widely separated coasts has been caused by the 
splitting up of this continent. 
Prof. A. REICHENSPERGER.—Probability of species-transformation in South 
American Myrmecophiles (11.0). 
Mr. G. E. H. Foxon.—Functional adaptation in crustacean larve (11.30). 
In the Decapod crustacea there is a primitive scheme of development, 
variations of which are found in different groups. These variations are 
seen to be intimately related to function. This primitive scheme consists 
firstly of naupliar stages where the head appendages are the swimming 
organs ; these stages are followed by those in which the thoracic appendages 
are the swimming organs, and then finally the pleopods take on this function. 
In most Decapoda the nauplius is suppressed : this means that the stage in 
which the thoracic appendages are natatory is not already committed to 
forward movement. Movement is found to take place in directions other 
than forwards, and this is correlated with the existence of the respiratory 
current which flows from behind forwards. Movement in directions other 
than forwards makes functional continuity between the stages in which 
the thoracic appendages are natatory and those in which the pleopods 
subserve this function impossible. ‘ Metamorphosis ’ between these stages 
