Walter Frank Raphael Weldon. 1860—1906. 
13 
headquarters in the Bahamas Weldon went with two friends to North Bimini 
in the Gulf stream and enjoyed immensely his first experience of tropical or at 
least semi-tropical seas. He made considerable collections, but his published 
results were confined to " H aplodiscus piger\ a new Pelagic organism from the 
Bahamas" (8), and a "Preliminary Note on a Balanoglossus Larva from the 
Bahamas" (9). Haplodiscus was netted near the Island of New Providence. It 
is a member of the Acoela, the most simplified of the class Turbellaria, and 
for some time Weldon's account was one of the most complete we had of any 
member of this group. Working at the Balanoglossus material in 1887, Weldon 
found that his results differed from those reached by Professor Sprengel. He 
accordingly went to Giessen at Easter, — his second visit to Germany, the first 
having been at Christmas, 1886 — and finally handed over to Professor Sprengel 
the whole of the Balanoglossus material he had collected in the Bahamas. 
During the Lent and May terms Weldon came up from Cambridge and gave a 
course on Economic Entomology to the forestry students at the Royal Engineering 
College, Cooper's Hill. The summer and autumn of this year involved a meeting 
of the British Association at Manchester, a visit on Chlorine business to France, and 
later, collecting and working in Guernsey. The Christmas was spent at Plymouth. 
In 1888 the buildings of the Marine Biological Laboratory in Plymouth were 
nearly completed, and the visits to Plymouth now replaced those to Guernsey. To 
the Marine Biological Association Weldon gave both time and sympathy during 
the rest of his life. His annual visits of inspection to Lowestoft during the last 
few years were always a great pleasure to him, and he was preparing for and 
talking of this year's visit only a few days before his death. Lent and May terms, 
1888, were spent as usual in Cambridge, but June to December were given up 
to Plymouth, with a brief Christmas holiday in Munich. And here we must 
note the beginning of a new phase in Weldon's ideas. His thoughts were dis- 
tinctly turning from morphology to problems in variation and correlation. He 
has left on record the nature of the problems he was proposing to himself at this 
time and they are summed up as follows : 
(1) The establishment of a new set of adult characters leading to the 
evolution of a new family has always been accompanied by the evolution of a new 
set of larval characters leading to the formation of a larval type peculiar to the 
newly established family; the two sets of characters having as yet no demonstrable 
connection one with the other. 
(2) The evolution of the adult and that of the larval characters peculiar to a 
group advance pari passu one with the other, so that a given degree of specialisa- 
tion of adult characters on the part of a given species implies the possession of a 
larva having a corresponding degree of specialisation and vice veisa. 
The next year was to place in Weldon's hands a book — Francis Gallon's 
Natural Inheritance, by which one avenue to the solution of such problems, one 
quantitative method of attacking organic correlation, was opened out to Weldon ; 
