1883.) On the Morphology of Arteries, especially of the Limbs. 505 
Fic. 15. Canthocamptus, sp. n., stylets of female. 
“# 16, “ 
oe: 2 fifth foot of female. 
“ 18. Diaptomus “ sanguineus,” fifth feet of larva (8). 
* fifth feet of larva (2). 
ir abdomen of larva (@). 
mS, " fifth foot of adult (3). 
yaey r: antenna of adult. 
“ 23. Diaptomus “castor,’ margin of last segment (<j). 
“ag ; 66 
4 margin of last segment ( Ẹ). 
25-28. Cyclops pectinatus. 
29. Diaptomus pallidus, inner ramus of fifth foot (H) 
10: 
REMARKS ON THE MORPHOLOGY OF ARTERIES, 
ESPECIALLY THOSE OF THE LIMBS.’ 
BY FRANK BAKER, M.D. 
F is generally taken for granted that the variability of arteries 
is such that they are of but little use in morphological studies. 
Anatomists are usually of the opinion that since the function of 
the arteries is to nourish the tissues, their course from the heart 
to their destination is of too slight importance to the race to have 
become a fixed character, and all search for law is abandoned. 
But it is questionable whether some biologists have not too 
hastily come to this conclusion. 
Morphological laws are always obscure when studied in the 
adult individual alone. To trace them we must examine the dif- 
ferent phases of individual development and investigate the anat- 
omy of related forms. 
There is a period when the embryo of a vertebrate animal is 
a6 Provided with a proper vascular system. During the early 
Stages of the segmentation of the ovum, no vessels exist, the 
young cells receiving the necessary nutriment from an interstitial 
la, as do those of the lowest Protozoa. 
This stage is of short duration. Throughout the minute disk- 
Object which is hereafter to be a fully developed verte- 
brate, certain cells appear, of a slightly reddish color, dotting 
f the disk in a peculiar marbled manner. From their appearance 
and isolation these are known as d/ood-islands. They touch each 
A finally as they increase in number, either at some part of 
ai 1A) ; 
ares of a paper read hefore the Montreal meeting of the Amer. Assoc. for 
= Beement of Science. 
