STUDIES ON EARTHWORMS, 253 
cheeta, the closed. vascular system consists of a dorsal and 
a ventral longitudinal trunk, together with a typhlosolar 
trunk in the intestinal region. In the anterior region of the 
body, paired commissural vessels or “lateral hearts” connect 
the dorsal with the ventral trunk. In Pontodrilus, a pair 
of longitudinal lateral trunks (“ intestino-tegumentary ” vessels 
of Perrier) are added to these three: these lateral trunks rise 
from a capillary network on the alimentary tract and pass 
forward to a similar network on the wall of the pharynx ; 
these lateral trunks are nowhere in direct communication with 
either the dorsal or the ventral trunk. The lateral longitudinal 
trunks occur in Lumbricus, where they rise as a pair of 
branches from the dorsal trunk in somite x. In Urocheta 
[in Microcheta], and possibly in Pleurocheta, they have 
the same arrangement as in Pontodrilus. These trunks 
have not been described in other genera. There is a sub- 
neural trunk in all forms, except in Pericheta, Pleuro- 
cheta, Pontodrilus [and Microcheta]. 
From these longitudinal trunks, of which the dorsal and 
ventral are chiefly contractile, paired vessels pass to the septa, 
nephridia, body wall, and alimentary tract; in these organs 
they break up into networks of capillaries, whence the blood 
is again collected by vessels which returns it to the main 
trunks. In Pericheta and Perionyx Beddard has shown 
that there are capillaries in the epidermis itself similar to 
those known in the leech. Howes has figured in the ‘ Biolo- 
gical Atlas’ a small “infra-mtestinal” vessel, closely 
attached to the ventral wall of the intestine in Lumbricus; 
this I have not myself seen, nor is it mentioned by M. Jaquet 
(49) in his description and figures of injected specimens of this 
genus. But Mr. Beddard has informed me that he has seen it 
in Acanthodrilus. Besides the “lateral hearts” in the 
anterior somites, there may be also commissural vessels in the 
intestinal region. These in Lumbricus pass from the dorsal 
to the subneural trunk. I have found that the organ in . 
Titanus, which Perrier regarded as part of a lateral heart 
and called “ ventricle,” is really an intestinal gland. 
VOL, XXVI,—NEW SER. s 
