
320 THE AMERICAN’ NATURALIST.’ [VoL XXXVI. 
was the first to describe the arrangement of vessels to the 
integument, showing that the capillaries of the parietals 
(** commissurals ") are directly continuous with those of the 
véntro-tegumentaries, and that loops of these-capillaries lying 
just beneath the. cuticle have the function of respiration. He 
has shown also that in somites VIII to XIII inclusive the sub- 
neural has a branch which supplies the nephridium and setiger- 
ous glands and anastomoses with the lateral. The lateral has 
connections with the dorsal in X and XII, as above described. 
Anastomosing vessels continue backward through XIII and 
XIV, making connections with the subneurals at each septum. 
These points have been verified by the present writers, but 
Harrington's statement that the true parietals (**commis- 
surals") are absent in XIV and XV they cannot confirm. 
True parietals are always found in all somites back of XII, and 
occasional worms clearly show anastomosing vessels continuing 
backward from the laterals, connecting with the parietals of 
one or two somites.. The anastomoses between the laterals 
and subneural have not always been found by the present 
writers in all.the somites mentioned. 
Harrington studied the course of blood flow iy watching 
the pulsations of the vessels in small specimens of -Lumbricus 
under a dissecting lens. He concludes that the blood flows 
forward in the dorsal, downward in the hearts, backward in the 
ventral, into the dorsal from the dorso-intestinals and out from 
it into the parietals (* commissurals "), forward in the laterals, 
and either forward or backward in the subneural. 
The senior author has made observations on the course of 
the blood flow in connection with class work for a number of 
years. During this time the direction of flow in the subneural 
has been demonstrated in many student dissections, the result 
constantly agreeing with that stated below. The observations 
reported here have been made on the largest worms obtain- 
able, anesthetized and opened under physiological salt solution. 
The course of the flow in each vessel has been determined by 
the three methods of clamping, cutting the vessel, and watch- 
ing the pulsations where these are visible. Injecting the 
dorsal vessel was tried several times, but as yet no facts 
