SUB-ORDER B TREPOSTOMATA al 
Filicea, d’Orb. (Laterocea, VOrb.), (Fig. 447). Zoaria erect, with sub-cylindrical 
branches bearing apertures on all sides. 
C 
\\ Y 
Filicea velata, Hagw. sp. Upper Cretaceous; Maestricht, Holland. 4, Branch, 1/;. 6, Surface of same 
enlarged. C, Vertical section (atter d’Orbigny). 

Fic. 447. 
Family 12. Melicerititidae. 
Zoaria ramose, bifoliate, or uni-lamellate. Zowcial tubes dilating outwardly, with 
perforated walls, Front of zowcia 
partly covered by a perforated plate. 
Vicarious avicularia scattered among 
the zowcia. Cretaceous. 
A 
The members of this family differ 
widely from the true Cyclostomata. 
They may be Mesozoic representatives 
of the Palaeozoic Cryptostomata, some 
of which, particularly Prowtel/a, they 
greatly resemble. But, on the other 
hand, the presence of avicularia, which Fic. 448. 
are as yet entirely unknown among Structure of walls and parenchymal cord in Homotrypa callosa, 
Palaeozoic Bryozoans, perhaps M- Ulr. (4, 35/3); Stictoporella frondifera, Uly. (B, 35/3); and Rete- 
dicates even stronger affinities with pore columnifera, Busk. Recent. (C, 6/1.) 
the Chilostomata. 
Semielea, d’Orb. (Reptelea, etc., VOrb.) ; Retelea, Clausimultelea, dOrb. 
Elea, VOrb. Flattened, branching, or anastomosing stems, or broad leaves, pori- 
ferous on both sides. 
Meliceritites, Roemer (Escharites, Roem.; Inversaria, Hagw.; Nodelea, Multelec, 
@Orb.) Cylindrical branching stems, poriferous on all sides. 

Sub-Order B. TREPOSTOMATA. Ulrich.! 
Zoecia directly superimposed upon one another so as to form long tubes intersected by 
straight or curved partitions (diaphragms and cystiphragms), representing the covers and 
1 [Two regions of the zocecial tubes are distinguishable, an axial or “immature” region, in which 
the diaphragms are remote, the walls thin, and the tubes prismatic through contact ; and a peri- 
pheral or “mature ” region, in which the tubes bend outward, the walls are thickened and otherwise 
modified, the transverse partitions more abundant, and interzocecial elements (acanthopores, meso- 
pores, or mere strengthening tissue) are developed. 
Waagen and Wentzel and others erroneously assert that the mesopores and acanthopores, occur- 
ring so commonly in this sub-order, are young zoccia or ‘‘corallites.” With very few exceptions, 
these really very different elements are not developed until the zoarium has reached the mature 
stage, in which new zocecia cease to be given off. The origin of mesopores (/,e. all cells occupying 
interzocecial spaces, whether invested with separate walls or not) is due to the same necessity which 
