86 PERCY SLADEN TRUST EXPEDITION 
the flat opercular plate. The latter is circular, rather thick and quite soft ; this condition 
may I think be due to the fixative though I am not sure whether the corrosive sublimate 
used contained any acid with it or not. At any rate, the appearance is much more that 
of a softened calcareous plate than of a chitinous one. 
Genus VERMILIOPSIS, Saint-Joseph (44) 1894. 
Generic characteristics: 1. Collar setz simple blades. 2. Uncini with fairly 
numerous teeth, the most anterior are larger and blunter than the rest. 3. Abdominal 
setee geniculate. 4. Some thoracic sete are bladed sickles (setee of Apomatus), thus 
differing from genus Vermilia with ordinary bladed setz only. 5. Operculum with a 
horny somewhat cylindrical or conical cap. 
19. Vermaliopsis pygidialis (Willey) (Plate 9, fig. 11). 
Vermilia pygidialis, Willey (50) 1905. 
Specific characteristics: 1. Branchize with ocelli and elongated often much swollen 
ends free from pinne. 2. Operculum with a conical (sometimes truncated) chitinous 
cap (fig. 116). 3. Uncini with 13 or 14 teeth. 4. Terminal dorsal gland generally 
present. 
Localities. One large specimen from Ras Osowarmembe, Zanzibar, in 10—15 
fathoms; others from Suez and Suakin in Mr Crossland’s collections. One specimen 
from Suvadiva, Maldive Group and a portion from Funafuti in Prof. Stanley Gardiner’s 
collection. Tubes ridged longitudinally and attached to the under sides of stones, &c. 
Two specimens are about 25 mm. long but the others only 15 mm. or less without 
their gills, z.e. about the size of Willey’s specimen—one small specimen is regenerating its 
collar, branchize and anterior thoracic segments. The general colour during life is “ bright 
pink or red, the gills being banded with white.” There are from 10—15 pairs of bran. 
chize ; their swollen ends appear to be glandular, though they are not so much developed 
as in Salmacina dystert. The pyriform ocelli are arranged in groups along the outer side 
of the rachises. 
The thoracic membrane is short and between the ventral borders of the thoracic 
uncinigerous tori is a depressed shield-shaped space with its broad end forwards. The 
terminal dorsal gland in some preserved specimens appears brownish and chitinous, in 
others whitish. po 
The operculum is often covered with a reddish or white calcareous incrustation 
(fig. 11a). When this was removed the translucent, light brown, horny cap was 
revealed. This is in most somewhat truncated (fig. 11b) and has several deep brown 
rings round it. In the specimens collected in August at Suez there is no incrustation 
and the horny cap is quite conical and dark in colour. The incrustation is specially 
noticed in specimens collected in November and February. The specimen from Suvadiva 
Atoll is without any incrustation. 
This species differs from Vermiliopsis glandigerius, Grav., in its branchize and oper- 
culum; its pedicle too is not ribbon-like, though it is certainly much wrinkled and 
swollen below the vertically placed horny cap. 
