of the Virginian Coast. 65 
Fam. SABELLID^. 
SABELLA {L.) Mgrn. 
Sabella microphthalma Verrill. 
Invert. Animals of Vineyard Sound, etc., p. 618. 
POTAMILLA Mgrn. 
POTAMILLA TORTUOSA 71. Sp. 
PLATE X, FIGS. 149-153. 
Branchiae, six pairs, colorless, transparent, with trans- 
verse markings of brown and white, and a green centre, 
connected at base for a short distance by a membrane. 
Pinnae often with same markings as stem. The first pair 
(dorsal) of branchiae are without eyes. The 2d, 3d, and 
4th may have from one to three convex dark red eyes, 
which are placed at equal distances from each other, the 
outer one being about half-way out on the stem ; their 
transverse diameter equals the width of the stem ; longi- 
tudinal diameter a little longerthan the transverse. Fifth 
and sixth pairs of branchiae without eyes. 
The ventral sulcus is continued on the dorsum, but is 
hardly perceptible save on the first three segments. An- 
terior part of body usually composed of eight segments, 
but may have seven, eight or nine. Each of these seg- 
ments has its ventral surface divided into two equal parts 
by a transverse impressed line. Back of these the ventral 
sulcus divides the ventral surface of each segment into 
lateral quadrangles, whose length is double their width in 
front; the length becoming less as the segments shorten, 
they finally become squares. The tentacles are flattened, 
triangular at base, becoming subulate further out ; length, 
about one-third that of the superior branchiae. 
Pinnae long, densely ciliated. 
All the setae of the first segment are capillary, similar 
to f. 149, but with narrower margin. The manubrium of 
the anterior uncini js very long (f. 152). The short cap- 
