Ornithology, Evolution, and Philosophy 123

Classification 331
When the Japanese attacked China, Weidenreich had to flee again and came to
America, where he was located at the American Museum. He loved to drop in on me
once in a while to talk German to somebody. Obviously he was rather homesick
for Germany. We always had very interesting conversations. Having apparently
learned his English rather late in life, he still occasionally mixed the two languages,
this sometimes leading to rather funny statements. In the last year of his life he
told me that he would prefer not to go back to Woods Hole this summer because
the diet there did not suit him ‘on Sundays they always serve baked bones.’ And
I, of course, understood at once what he wanted to say, but it took me a minute or
two before I realized how funny his remark had been. Fortunately, he had made
some excellent plaster castes of Peking Man so that the tragedy of the loss of the
original material is not quite as great as it otherwise would have been. I learned
a great deal about the fossil history of man from my talks with Weidenreich.”
Snails
The genus Cerion is famous in the evolutionary literature because it poses a challenge
to anybody interested in the nature of species. There is a rich literature, and
after almost 100 years of controversy, there was a majority explanation among
the specialists. However, when Mayr began to study this genus he soon realized
how little we really understood its variation. In March–April 1952, he spent several
weeks on Bimini Island, an outpost of the Bahamas, to collect Cerion snails.
Two facts stimulated him to undertake this research: (1) No reproductive isolation
had developed among taxa that were strikingly different; seemingly indiscriminate
interbreeding took place, where they came into contact. (2) These hybrid
populations showed no increases in the coefficients of variation for size and shape
characters but were highly variable with respect to sculpture (presence of ribs)
and coloration. There was no clear-cut correlation between shell type and habitat.
All colonies on Bimini seemed to be conspecific. Mayr planned to go back and
therefore marked all individuals on certain carefully measured squares in order to
determine their survival and dispersal during the later years. These experiments
were not followed up because of Mayr’s move to Harvard. In a publication on
this project (Mayr and Rosen 1956j), most of the measurements of the material
collected and calculations were made by the coauthor.
On the suggestion of Bill Clench at Harvard University, Mayr went to the Banes
Peninsula in Cuba, where the richest assemblage of Cerion species occurs. Here
again he found a narrow hybrid zone between two extremely different taxa, and
again in this belt the coefficient of variability did not rise appreciably for dimensionandshape.HealsofoundzonesofoverlapofCerion
species not very different
in morphology and encountered individuals of certain taxa in strikingly different
habitats (exposed sandy beach and on top of a raised coral reef in open woodland).
On the other hand, along a stretch of flat exposed sandy beach about 4–5
exceedingly different morphological types occurred in an identical environment.
Mayr was unable to go back to Cuba, when Fidel Castro took over the government