f. Hitchcock— Causes of Variation. 51 
siurely due to the favorable conditions of life and the abun- 
of food available. It is true, as already said, this may be 
ieuardid as a mere statement of the influence of environment 
causing variation, but a careful consideration of the subject will 
show that there is a broad distinction between environment as 
a cause of variation, and adaptation to environment ; for in this 
beneficial. In the case under consideration, however, an exam- 
ination of the changes that have taken pl ace does not indicate 
any possible benefit to the organism. ‘The multiplication of © 
chamberlets necessitates very intimate interecommunication for 
the transference of food and the continuation of the processes 
of life. The organism is not thereby better adapted to its 
surroundings, but is made more dependent for its existence 
upon the continuance of the favorable conditions under which 
it has developed. The advance in complexity—tke multipli- 
cation of sh anne ace only be possible under the most 
favorable conditions, for all the nutriment received by the 
interior segments must be collected by the sarcode at the mar- 
gin of the shell, and the necessary food could only be obtained 
where the supply was abundant. It may be conceived that if 
0. complanata were placed in situations less favorable as regards 
food it would die of starvation owing to the quantity of inner 
sarcode requiring nourishment, while O. éenuissima needs only 
more favorable conditions as regards food, and perhaps temper- 
ature, to become as highly complex in structure as the last- 
- mentioned species. As a further proof of the influence of 
environment leading to changes which cannot be regarded as 
special adaptations, in the usual meaning of the word, the forms 
of O. complanata found on Fiji reef are especially characterized 
by thick, plicated margins, as though growth proceeded with 
too great rapidity to produce symmetrical disks, and these 
forms are associated with the largest representatives of the 
eci 
The distinction above referred to seems an important one, 
which, if it has already been recognized, has not been prom- 
inently fechas forward in the writings with which I am famil- 
ore the Biological seers the subject was briefly. 
POR a in the following wor 
‘Regarding the subject from this point of view we are led to 
examine more closely the relations between the spiral and the 
cyclical methods of growth. Their intimate pois is 20 
noticeable when we observe how one has been d erived carat Le 
