168 Prof. M‘Intosh’s Notes from the 
has a slight web on the inner side. The pinne are of 
moderate length and closely arranged in a double row along 
the inner border, the basal region of each being wider ; 
thereafter it tapers to the blunt tip. None of the camerated 
chordoid tissue so characteristic of the Sabellid branchiz is 
present either in filament or pinna, though it is clear that 
cellular supporting tissue must be in both. The filaments 
are best developed toward the dorsal edge of the fans. 
Toward the tip of the filament the pinnz diminish in 
length, and end in short papille at the base of the free 
distal processes, into which, so far as can be observed, only 
a blood-vessel enters. When thrown off, the vitality of the 
branchize is considerable. . 
A bilobed fillet lies between the bases of the branchize 
dorsally, and at its ventral edge is a triangular process. 
Ventrally is a wide gap leading to the mouth, which has a 
short fissure in the lower lip. 
In the small variety from Herm the subulate process at 
the tip of the branchial filameut and the pinne are propor- 
tionally shorter, but the structure is the same. 
The dorsal lp, ciliated and often bordered with brown, 
is placed between the first two dorsal branchie, and carries 
two palpi. This is separated from the mouth by the ventral 
hip, which is colourless. 
The body in the free example is somewhat broad an- 
teriorly, and tapers from the middle gradually to the tail, 
which has a terminal anus. It is somewhat flattened both 
dorsally and ventrally, a median groove occurring dorsally 
in the anterior region and ventrally in the posterior region. 
The anterior region, moreoyer, has the broad membranous 
web, continuous anteriorly with the dorsal fold of the 
collar, and which passes laterally above the bristle-tufts, 
ending ventrally by joining that of the opposite side behind 
the last bristle-tuft of the region. This membrane is sup- 
ported by a greatly developed alar or dorsal process of the 
foot, which tapers distally, and is freely mobile, so that 
when the annelid withdraws itself into the tube this mem- 
brane and the bristles are closely applied to the dorsum. 
No spine supports the alar process, so that the muscles of 
the bristles suffice for all its movements, which would appear 
to be partly respiratory, since its blood-vessels are finely 
reticulated. 
The pore for the thoracie organ is placed on the second 
setigerous segment in the mid-dorsal line (De St. Joseph). 
The “ thorax” is greenish, the alar membrane veined with 
green, and each segment is distinguished by a band of red. 
