306 MANAYUNKIA (HAPLOBRANCHUS) ASSTUARINUS. 
are long, richly ciliated dorsally, and have a large green blood-vessel. A pair of eye-spots 
occur at the side of the prostomium. The collar is formed of the peristomium. The mouth 
is between the palps and the bases of the peristomial tentacles. 
The body’ has twelve segments, of which nine form the anterior and three the posterior 
region. The segment behind the peristomium bears dorsal capillary bristles only, viz., 
forms (Plate CXXXV, fig. 20) with long tapering winged tips, and shorter forms with 
broader and shorter wings, which are said to occur only on one side of the axis. The next 
segment also has dorsal capillary bristles, but in addition ventral crotchets (Plate CXXXV, 
fig. 20a), which have short, curved shafts and rather broad serrated tips. In the posterior 
region the hooks are dorsal and the bristles ventral in position. The bristles are more 
slender and longer than the anterior, with winged tips. 
The alimentary canal is comparatively simple, being cylindrical in front, constricted 
in front and rear, has an ovoid swelling in the fifth bristled segment, and then diminishes 
till it reaches a rectal enlargement. It is ciliated posteriorly, and anteriorly has brown 
pigment in its walls. The blood is green, and the dorsal vessel is bifurcate anteriorly and 
posteriorly before joming the ventral vessel. In the tenth and eleventh segments a trunk 
connects the dorsal and ventral vessels, and in the females similar trunks occur in the fourth 
and fifth segments. Vessels also probably form a sinus around the intestine in the central 
region of the body. ‘Trunks enter the head and dilate into a sinus at the base of the 
peristomial tentacles as in allied forms (e.g. Fabricia). Paired bodies (probably segmental 
organs) occur in the segments 10—12 at the bases of the feet. In the third are two 
bodies which may be these organs modified to perform the functions of tubiparous glands, 
and they open at the bases of the feet. 
Reproduction.—The sexes are distinct, the sperms in various stages of development 
floating in the body-cavity of segments 7—9, and they are confined to the central region 
by a membrane. The “spermatospheres ” are elongated rope-like bodies. Ova are found 
in segments 4 and 5, and are large. They probably escape by rupture of the body-wall. 
Bourne (1883) considered that this form pertained to the Serpulidee from its capito- 
branchiate nature, but differed in so far as the branchial tentacles are devoid of any 
secondary filaments or any trace of “cartilaginous” support. It agrees with the 
Sabellidze in the “absence of any thoracic membrane and operculum.” It agrees with 
Amphiglena, Fabrica and Amphicorina in the modified segmental organs of the second 
segment. ‘There is no trace, however, of auditory capsules or caudal eyes. They all agree 
with Manayunkia in the simple structure of the head, in which the prostomium is not 
completely fused with the peristomium, and presents prostomial tentacles and palps. The — 
peristomial collar, completely absent in Amphaglena, is only slightly developed in the other 
forms. Prof. Bourne had some doubt about the palps, and their blood supply would lead 
one to attribute to them a respiratory function. He likens the tentacles to the dorsal and 
ventral divisions of the foot, and thought they might be peristomial, but De Quatrefages 
states that the branchie of the Serpulide receive their nerve-supply from the supra- 
cesophageal ganglion and consequently they are prostomial. “Claparéde and Mecznikow 
have, however, shown that in Dasychone lucullana they are peristomial.”’ 
' T am indebted to Mr. Shrubsole for aid in procuring examples per Mr. Bolton. 
