Identification of the Species of Cephalodiscus, 409 
The only species outside the subgenus Deméothecia that 
has spines on the coencecium is C, gilehr iste, 
The length of the zooids given in the key is that from the 
free ends of the arms to the end of the trunk, not including 
the stalk. 
I. Cavities of the ccencecium in the form of tubes. 
Hach tubular space with a single orifice, and 
occupied by one zooid and ita” buds. Arms 
without end-swellings and refractive beads. 
A. Coencecium in the form of a branching 
system, with the newest tubes at the apices 
ofthis, branches ses ss 8 Sk A ee ee 
a. Internal ends of the tubes communicating 
by a labyrinthie system. 
1. Branches massive, fragile, with abun- 
dant fragments of shell embedded ; 
each ostium with a short, blunt lip, 
but no peristomial tube. Zooids 
45 mm., blackish; arms 8 or 9 pairs. agy/utinans. 
6. Internal ends of the tubes blind. 
2.. Branches massive, fragile, with abun- 
dant fragments of shell embedded ; 
each ostium with a short peristomial 
tube. Zooids 3°56 mm., white; arms 
Belally: EPA As 53, ihe ae 6 wane Aen nn), CDARSE 
5. Branches fairly long, slender, not fragile, 
with numerous long s spines; brownish ; 
ostia with or without peristomial tubes. 
Zooids 1°6 to 1°8 mm., blackish when 
alive, brown in preserved material, 
with blackish margin to anterior edge 
of shield ; arms usually 6 pairs ..., gélchristi. 
4, Branches medium or slender, orange- 
coloured, nospines ; each ostium witha 
single-lipped peristomial tube. Zooids 
2°5 mni., whitish; arms 6 pairs .... levinseni. 
— 
5. Branches massive, rarely slender, greyish 
or brownish, no spines; each ostium 
with a short, single-lipped peristomial 
tube. Zooids 4:0 to 60 mun., blackish ; 
arms usually 7 pairs, each with two 
black bands along the axis.......... magrescens, 
B. Coeneecium in the form of a hemisphere, 
cone, or cake, with the newest tubes at the 
edges ; basal ends of the tubes blind . Orthoecus. 
6. Cclony bulky and massive, tubes as 
common ccenccial substance firm ; 
each ostium with a single thick lip, 
Ann. & Mag. N. Hist. Ser. 9. Vol. v. 
bo 
WH 
