A NEW BRANCHIATE OLIGOCHATE. 331 
The remaining external characters of Branchiura are of 
less importance. The prostomium is conical, short, and 
rounded in front (see fig. 4). Each of the anterior segments 
is biannulate, as in many Tubificide. The dorsal seta 
bundles alone contain capilliform sete, and there are at the 
most two of these toa bundle. The other sete of the dorsal 
bundles are “ crotchet-shaped.” Very frequently the upper 
fork is worn away, so that the sete resemble those of certain 
Lumbriculide, and appear to be simple sigmoid setz, unnotched 
at the extremity. The ventral sete are of one kind only— 
* crotchet-shaped.” There is no ‘ cephalisation” shown by 
the sete. The second segment of the body has both dorsal 
and ventral bundles. The first two pairs of bundles, however, 
sometimes have no capilliform sete, but this is probably acci- 
dental or an individual peculiarity, since in a second specimen 
they were present. The number of short sete in the dorsal 
bundles of the first twenty segments or so is four to six, 
generally five; but generally six or seven in the larger speci- 
men. Further back the number of these sete in each bundle 
is less, being two or three. In the dorsal bundles of the most 
posterior segments there seem to be no capilliform sete. In 
this the worm resembles Tubifex. 
§ Vascular System. 
I studied the vascular system principally in the living 
worms, but also by following out the course of the vessels in 
transverse and longitudinal sections. The blood was dis- 
tinctly red in the larger vessels. The only contractile trunks 
are the dorsal vessel and certain of the circumcesophageal rings 
which connect it with the ventral vessel. The pulsations of 
the dorsal vessel pass from behind forwards, of the ‘hearts ” 
from above downwards. Both the dorsal and ventral blood- 
vessels run from end to end of the body. It is remarkable that 
the term “ dorsal” vessel! is quite inapplicable to the longi- 
1 Tt is curious to learn from Hisen (‘‘ Preliminary Report on Genera and 
Species of Tubificide,” ‘Bik. K. Svensk. Ak. Handl.” Bd. iv, p. 7) that 
something of the same kind occurs in Telmatodrilus, though reversed ; 
