SUB-ORDER C CRY PTOSTOMATA 283 
Thamniscus, King. Like Polypora, but branches bifurcating more freely, and with 
only a few dissepiments or none. Silurian to Permian. 
Phyllopora, King. Zoaria funnel-shaped, celluliferous on the outer side, and con- 
sisting of anastomosing branches, which form a regular, round-meshed network. 
Zocecia in two or more rows. Devonian and Permian. 
Ptiloporella, Ptiloporina, Hall. Silurian and Devonian. 
Ptilopora, M‘Coy (Dendricopora, de Kon.) Zoaria pinnate, the central branch much 
stronger than the oblique lateral branches, which are united by dissepiments. Zocecia 
in two ranges. Devonian and Sub-Carboniferous. 
Family 7. Acanthocladiidae. Zittel. 
Zoaria poriferous on one side only, pinnate or forming fenestrated expansion ; consisting 
of strong, central stems which give off numerous, smaller, lateral branches from their opposite 
margins. The lateral branches are free or unite with those of the next stem. Non- 
poriferous dissepiments absent.  Zoecial characters mostly as in the Fenestellidae. Silurian 
to Permian. 
Pinnatopora, Vine (Glauconeme, auct.) Zoaria small, delicate, with short, free, 
lateral branches given off frequently at regular intervals. Cells in two rows, one on 
each side of a moderate median keel. 
Silurian to Carboniferous. 
Septopora, Prout. Zoaria fenes- 
trated, flabellate, or leaf-like. Primary 
branches numerous, increasing by bi- 
furcation or interpolation ; the lateral 
branches uniting with those of adjacent 
stems. Reverse usually with fine striae 
and scattered dimorphic pores. Cellu- 
liferous side with two rows of zoccia 
arranged as in Pinnatopora. Chester 

Group and Coal Measures. Fic. 470. 
Acanthocladia, King. Like Pinnato- Fie. 469. Pachydictya __ foliata, 
; a : : *“Helopora spiniformis, Ulr. Ulr. Lower Trenton ; 
pord, but larger, stronger, and with Trenton; Tennessee. A, Ver- Minnesota. Tangential 
three or more ranges of cells. Coal] tical section, 4/4. B,Segment, section, Mj, (after 
2 1/, and 14/; (after Ulrich). Ulrich). 
Measures and Permian. 
Synocladia, King. Differs from Septoporw in the same manner as the preceding 
differs from Pinnatopora. Permian. 
Diplopora, Young. Essentially a Pinnatopora without lateral branchlets. Carboni- 
ferous. 
Ichthyorachis, M‘Coy, Penniretepora, V@Orb., and Ramipora, Toula, may belong here. 
Family 8. Phylloporinidae. Ulrich. 
Zoaria branching, celluliferous on one side only, the other side striated ; branches free or 
anastomosing. Zowcia more or less tubular, often with diaphragms. Hemisepta wanting. 
Ordovician to Coal Measures. 
Phylloporina, Ulrich. Branches irregularly anastomosing, with two to eight 
ranges of zocecia on the celluliferous side. Tabulated interstitial spaces generally 
present, closed at the surface. Ordovician and Silurian. 
Drymotrypa, Ulrich ; Ordovician and Silurian.  Chainodictyon, Foerste ; Coal 
Measures. 
The following genera of doubtful affinities may be provisionally appended here :— 
Proutella, Cycloporella, Worthenopora, Ulrich ; Cyclopora, Prout ; Paleschara, Hall. 
