56 Annelida GJicBtopoda 
and narrowed. In contraction this anterior part is about 
equal in length to the posterior (f. 127) and is somewhat 
shovel-shaped ; in extension it is double this length and is 
acute, conical. A very shallow incision at the end can be 
seen in alcoholic specimens; this was not noticed in living 
forms. 
Eyes two, small, circular, lateral, posterior. 
Antenna, arises about the centre of the head, delicate, 
subulate, in length not quite half the head. 
Dorsal ramus with dorsal cirrus but without proper feet 
or ramus. Cirrus on first segment a mere papilla, increas- 
ing in length to the fourth segment, where it is about 
one-third the length of the branchiae ; the first three are 
cylindrical ; the fourth, and all back of it, on the bran- 
chiated segments, have a small lobe, developed near the 
base, looking outward. On the non-branchiated posterior 
segments this cirrus loses the lobe, becomes somewhat elon- 
gated, very delicate, subulate. 
Ventral ramus, on first segment a minute cylindrical 
papilla, a little longer than the dorsal cirrus; increasing 
slightly in length to the fourth segment, where it is about 
one-half as long as the dorsal cirrus. Back of the fourth 
segment it is flattened (compressed) and becomes a fleshy 
lobe, rounded externally. It retains this form to about 
the 30th segment, where it again assumes the form of a 
cirrus, shortens progressively, and disappears at about the 
40th segment, after which segment the ventral rami are 
entirely without appendages. The ventral cirri are always 
just back of the ventral setse. 
Branchiae, begin on fourth segment, arise just within 
the dorsal cirri, taper slightly to near the end when they 
became suddenly acuminate ; they are usually directed 
inward and a little upward, their length being a little more 
than half the width of the body, so that they cross each 
