1883. ] The Hairy Woodpecker. 511 
The variation of the long thoracic and uterine arteries in females 
when lactation and gestation are established, is a familiar exam- 
ple. In animals that move slowly or remain for some time under 
water, it seems to be sometimes necessary to provide for a slow 
purling of blood along nervous trunks. In sloths, the Ornitho- 
thynchus and the manatee the main trunks break into plexiform 
arrangements, and in Cetacea large plexuses encircle the spinal 
cord. It is conceivable that the original capillary form has never 
been entirely overcome in these cases. So too in the alimentary 
canal of man. This, the oldest part of the body when viewed 
phylogenetically, has also the oldest form of circulation. The 
activity required is slow, but constant. Removed from external 
influences, it has not become as highly differentiated in function as 
the periphery of the body. The polypoid activity of the cells is 
best kept up by a gradual welling of the blood through a series 
of encircling capillaries. Even the larger branches show that 
they are incompletely differentiated. The branches of the mes- 
enteric arteries do not each separately carry blood to the part 
they are to feed, but unite by cross anastomoses in a series of 
loops, the whole resembling an enormously enlarged capillary 
plexus, | . 
If this view of arterial morphology be correct, all varieties 
found in man and animals should be reducible to the general case 
Prefigured by the radiate fin of fishes. Any important series of 
exceptions that cannot be derived from the archetype would over- 
throw the theory. 
W 
:0: 
THE HAIRY WOODPECKER. 
A. G. VAN AKEN. 
HE pert, comely and invaluable bird designated in science as 
7 Picus villosus Linnæus, though known in general parlance 
-Simply as the hairy woodpecker, or “ sap-sucker,” has been various- 
ly Portrayed by those attempting his biography. Careful inquiry 
a among the masses discloses the fact that he is well and favorably 
‘ ‘Known only to the few specialists in this department of natural 
one history, while diversity of statement and contrariety of conclusion 
a as the rule. 
bo ) the present instance our purpose is merely to adduci 
na fide observations, gleaned during the past few seasons in New 
e some 
