230 A Study of Garden Lettuce. [ March, 
were acquired which led the creature, ż4en neither frigate-bird nor 
gull, to get its food by association with some messmate more able 
to procure it. Then these two forms diverged from the common 
ancestor, acquiring new traits from new environments. As the 
frigate-birds gained dominion of the air, they also gained domin- 
ion of species of fish-hawks, which became enslaved by them. 
But the hawks also diverged into other species, one or more of 
which retained the terror, but not the discipline, and, when com- 
manded, would not comply, through sheer ignorance of the nature 
of the demand. When the birds met with a specimen of this 
branched stock, they urged obedience with such vigor as to result 
in the death of their unfortunate victim. Then the old ancestral 
habit, which may be had outlived a thousand generations, comes 
into play, and they stand on the dead body, in pure friendship, 
waiting to be fed! What do they know of the mystery of death? 
The only weak place is where the branching hawk forgot the duty 
of fishing for its master, but not the terror of its presence. But 
then fear is what prompts it to escape from an enemy and thereby 
save its life, so that this emotion would properly survive the 
other. 
:0: 
A STUDY OF GARDEN LETTUCE. 
BY E. L. STURTEVANT, M.D. 
ty the New York Agricultural Experiment station, in 1885, 
eighty-three distinct varieties of lettuce were grown undef 
nearly two hundred names. These lettuces present to the on- 
looker three distinct form-species, the lanceolate-leaved, the Cos 
and the cabbage. It is a pertinent inquiry as to whether these 
form-species are of distinct origin or have been produced by cul- 
tivation within recent times, and we hence offer a succinct ac- 
count of our historical investigations. 
* The lanceolate-leaved form is represented with us by one vari- 
ety only, the deer’s tongue, introduced as a seedsman’s novelty in 
1883. The type of this form is perhaps referred to by Pliny, lib. 
XIX, c. 38, “ præterea longi et angusti intubi similis,” as this plant 
_of ours has a chiccory-like appearance in some stages of its 
growth. It is certainly mentioned by Bauhin? in 1621, and cred- 
ited in his synonomy to Castor, 15855 ; and is figured by Bauhin? 
1 Pinax, ed. of 1621. 
* Prodromos, ed. of 1671, 
