PIXELL—POLYCH ATA OF THE INDIAN OCEAN 85 
There are 6 uncinigerous tori on each side leaving between their ventral ends a 
triangular space with its apex towards the posterior. 
The thoracic uncini are 86 » long and have about 15 pointed teeth in addition to 
the large anterior gouge-shaped one (figs. 9d and e). 
POMATOLEIOS, n. g. 
Generic characteristics: 1. Collar sete and eyespots absent. 2. Uncini with 
fairly numerous teeth, the most anterior being larger and gouged underneath (fig. 10d). 
3. Abdominal setze trumpet-shaped with one side produced into a long spine (fig. 10¢). 
4. Operculum flat with winged pedicle. 5. Tube with a flap over the entrance. 
18. Pomatoleios crosslandi, n. sp. (Plate 9, fig. 10). 
Specific characteristics: 1. All thoracie sete simple striated blades (fig. 100). 
2. Uncini with 10 or 11 teeth in both thorax and abdomen. 3. Branchize with very 
high inter-branchial membrane and long bare terminal filaments (fig. 10@). 
Localities. Ras Shangani and Chwaka. Numerous specimens but no tube present. 
Mr Crossland, however, gives the following notes. ‘Rough coiled tube, blue coloured 
especially inside and having a flap over the entrance: occurring many together not far 
below high water mark, e.g. on old boiler at Ras Shangani and at Chwaka near high tide 
mark down to half tide, but easiest to collect at high neap tide.” 
Mr Crossland also draws attention to the remarkable vitality of these specimens 
which he had some difficulty in narcotising. The tube appears to be quite exceptional, 
but unfortunately there are none present in the collection: the total absence of collar 
sete is also rare. Though numerous specimens, of total lengths varying from 4 to 
_ 14mms., have been carefully searched no sign of these sete has been found. Neither 
are there apparently any eyespots as in the genus Placostegus ; the specimens also differ 
in other obvious ways from this genus. Should still younger specimens than those that I 
have been able to examine be found to have collar sete, then this genus may be able 
to be included in the genus Pomatoceros. In Pomatoceros triqueter the collar sete are 
sometimes much reduced in the adult (Soulier 49), but according to Saint-Joseph (44) 
they are always present. 
The six fascicles of thoracic sete present are all alike, being composed of simple 
striated blades (fig. 106). 
The collar varies a great deal; the ventral lobes seem generally to be high and 
entire but folded as in fig. 10a, and they give rise to a small dorsal lobe or languet 
which lies just inside the dorso-lateral lobe of the collar. 
The branchize, 13—16 pairs, are remarkable for the height of their interbranchial 
membrane (fig. 10a); this joins them together for about half their height and nearly half 
of the free part is bare of pinnze forming a long tapering filament. 
The opercular pedicle is short and has thick lateral wings which end distally in 
straight edges close under the operculum. It arises almost in the middle line of the 
dorsal surface slightly, if anything, to the left and is attached towards the dorsal side of 
