I 886.] | Aguatic Respiration in Soft-shelled Turtles. 233 
various countries, but such evidence as I have here outlined 
` strongly supports the hypothesis that our three form-species of 
lettuce have originated from wild forms which have been brought 
into culture in different regions, and hence that our three form- 
species have different origin, The history of lettuce as published 
affords no clue towards settling this point. Lettuces are supposed 
to have been grown by the Persians some five hundred years be- 
fore Christ, and to have been introduced into China between the 
years 600 and goo of our era; they were mentioned by Chaucer 
in England in the fourteenth century, and reached America with 
Columbus. 
ve td 
AQUATIC RESPIRATION IN SOFT-SHELLED TUR- 
TLES: A CONTRIBUTION TO THE PHYSIOLOGY 
OF RESPIRATION IN VERTEBRATES? 
BY SIMON H. AND SUSANNA PHELPS GAGE. 
e was formerly supposed that in all reptiles the respiration was 
exclusively aérial at all periods of their life, and that the lungs 
were the only respiratory organs. We have demonstrated, how- 
ever, that in soft-shelled turtles (Amyda mutica and Aspidonectes 
Spirifer) there is in addition a true aquatic respiration. This is żin- 
dicated by three facts: (a) These turtles remain most of the time 
in water, and voluntarily remain entirely under from two to ten 
consecutive hours ; (4) while under water they fill and empty the 
mouth and pharnyx, about sixteen times per minute, by move- 
ments of the hyoid apparatus, the general appearance being like 
the respiratory movements of a fish; (c) the mucous membrane 
of the pharynx is closely beset with filanientatis processes, appéar- 
ing like the villi of the small intestine of a mammal or the gill 
filaments of Necturus. These processes are especially numerous 
along the hyoid arches and around the glottis, and are copiously 
Supplied with blood? 
‘A croton paper upon the respiration of Aspidonectes was presented to the 
A.A by the senior author in 1883, and printed on p. 316 of the Proceedings 
(Vol. xxxi). 
? So far as we know but two original observations (besides that mentioned in the : 
Preceding foot-note) have been previously made upon the Trionychidze bearing nee 2 
the subject of this paper : (a) In February, 1856, Dr. A. Sager called 
the processes in the pharynx of Aspidonectes, and co: ces < 
with the gill filaments of Necturus and the inner gills of tadpoles. o Professor L. 
