Small Ad for 
a Big Tour of the Orient 
Japan Air Lines has 35 very special 
tours to the Orient. Come, let us take 
you to the Orient of your dreams. 
Here is but one example: 
Mandarin Orient, 19-24 days, 
$3197-3675. All tours visit Hong Kong, 
Peking, Shanghai and Canton. Some 
tours also visit Tokyo, Penang, 
Singapore, Bangkok as well as certain 
cities in China. All tours fully escorted 
and most meals are included. 
Rates based on double occupancy and economy air 
fare from the West Coast and are subject to change. 
Additional charge for June-October peak season. 
Fc allToll free" 
I 800-835-2246* Ext. 143 
I for free tour information, see your travel 
agent, or mail this coupon today. 
I Japan Air Lines, P.O. Box 10618 
| Long Island City, Hew York 11101 
'JAL HAPPY H<dLIDA/S 
| JAPAN AIR LINES 
I Dear JAL: I've read your small ad and I'd like 
more details of the tours I've checked. 
I □ Mandarin Orient (3005) 
| □ Other Happy Holidays Tours 
| Name 
| Address 
. City State Zip 
..-'ll|| 
Travel Agent NH 0481 
‘Continental ti.S. only. In Kansas: 800-362-2421 
SPEND A WEEK AT CORNELL! 
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ation presented to it. In this sense, 
constraints of variation may direct the 
paths of evolutionary change as much 
as selection acting in its Darwinian 
role as a creative force. 
I have found Vavilov’s views very 
helpful in reorienting my own thinking 
in directions 1 regard as more fruitful 
than my previous unquestioned con- 
viction that selection manufactures al- 
most every evolutionary change. In 
studying the relationship of brain size 
to body size, biologists find that brains 
increase only one-fifth to two-fifths 
as fast as bodies in comparisons of 
closely related mammals differing 
only (or primarily) in body size — 
adults within a single species, breeds 
of domestic dogs, chimpanzees versus 
gorillas, for example. For ninety years, 
the large literature has centered on 
speculations about the adaptive rea- 
sons for this relationship, based upon 
the (usually hidden) assumption that 
it must arise as the direct product 
of natural selection. 
But my colleague Russell Lande re- 
cently called my attention to several 
experiments on mice selected over sev- 
eral generations for larger body size 
alone. As these mice increased in size 
across generations, their brains en- 
larged at the characteristic rate — a 
bit more than one-fifth as fast as body 
size. Since we know that these ex- 
periments included no selection upon 
brain size, the one-fifth rate must be 
a nonadaptive side product of selected 
increase in body size alone. Since the 
one-fifth to two-fifths rate appears 
again and again in diverse lineages 
of mammals, and since it may record 
a nonadaptive response of brains to 
selection for larger bodies within 
mammalian developmental systems, 
the parallel sets of races and species 
arrayed along the one-fifth to two- 
fifths slope in carnivores, rodents, un- 
gulates, and primates are non-Darwin- 
ian homologous series in Vavilov’s 
sense. 
In personal research on the West 
Indian land snail Cerion, my colleague 
David Woodruff and I find the same 
two morphologies again and again in 
all the northern islands of the Baha- 
mas. Ribby, white or solid-colored, 
thick, and roughly rectangular shells 
inhabit rocky coasts at the edges of 
banks where islands drop abruptly into 
deep seas. Smooth, mottled, thinner, 
and barrel-shaped shells inhabit calm- 
er and lower coasts at the interior 
edges of banks, where islands cede 
to miles of shallow water. The easiest, 
20 
