410 Mr. H. A. Baylis on 
edge of ostium thick. Zooids 4:0 to 
5:0 mm., blackish, fading to pale 
brown ; arms usually 8 pairs ...... solidus. 
7. Colony bulky and massive, or small 
and lax if young (rarus), tubes long, 
common ccencecial substance soft and 
spongy ; ostium without a definite lip, 
transverse or oblique, edge of ostium 
thin. Zooids 4:0 to 7-0 mm., brownish 
or greyish ; arms usually 8 pairs.... densus (including ra- 
(7ws and (?) anderssont). 
8. Colony diminutive, orange when fresh, 
pale in alcohol; ostia without definite 
lip. Zooids 2°2 mm., pale; arms 3 
PHES ne ees Rete sale tice Sigls opie: LICE 
II. Cavity of the ccencecium continuous, and occu- 
pied in common by the zooids and their buds. 
Coencecium branching, with numerous spines. 
Arms of zooids commonly with end-swellings 
beset with refractive beads ............ .. Demiothecia. 
a. Colony up to 200 or 250 mm, in height, 
coencecium amber-coloured or pale. 
9,10, 11. Colony much branched. Zooids : 
2-0 to 3:2 mm., erimson, brown, violet, 
or pale; arms 5 or 6 pairs. Species 
not easily distinguished, but hodgsunt is 
somewhat more robust, and with larger 
zovids, than dodecalophus ........+: .. dodecalophus, hodg- 
[sont, (tnequatus = 
[hodgsont), equatus. 
b. Colony diminutive and delicate, coencecium 
orange-coloured. 
12. Zooids 1:3 mm., orange-coloured, with a 
few tracts of black pigment; arms 5 
pairs, with end-swellings in buds. No 
males known ...... d Hee eae sdae pinn egraciha.: 
18. Zooids blackish; neuter zooids ]*3 mm., 
arms 4 pairs, no end-swellings; male 
zooids with one pair of arms only, with- 
out tentacles, numerous refractive beads. 
No females known....... ii tweeb eps siboge. 
LV.— Observations on the Genus Crassicauda. 
By H. A. Bay.is, M.A. 
(Published by permission of the Trustees of the British Museum.) 
Two sets of specimens from Deception Island, South 
Shetlands, kindly sent to the Museum recently by Mr. A. G. 
Bennett, throw interesting further liglit on this little-known 
genus of Nematodes. The host, in both these cases, was the 
Eee 
