SYSTEMATIC SYNOPSIS. 39 



Suborder I. Articulata. Zoarium divided into internodes, by 

 horny tubes at the nodes ; joints usually flexible. 

 Fam. 1. Crisiida. JSTo Jurassic representatives. 



Suborder II. Tubulata. Zoarium formed of monomorphic 

 zocecia, not divided into internodes; zooecia of elongated tubes 

 grouped into bundles or sheets, or linear series. 



Section 1 . Young zoarium Stomatoporiform or Probosciniform. 

 Fam. 1. Tubuliporida. See p. 41. 



,, 2. Entalophorida. See p. 137. 



,, 3. Idmoniidce. See p. 133. 



,, 4. Horneridce. No Jurassic representatives. 

 Section 2. Young zoarium. Cupuliform. 

 Fam. 5. Fascigeridce. See Pt. III. 



. Osculiporid<e. See Pt. III. 



7. Theonoida. See Pt. III. 



Suborder III. Dactylethrata. Zoarium multilamellar, usually 

 erect and dendroid ; largely composed of dactylethrae. (For 

 diagnosis see Pt. III.) 



Fam. l. Clamidce. See Pt. III. 

 ,, Z.Reticuliporida. See Pt. III. 



Suborder IY. Cancellata. Zoarium composed of simple zocecia 

 separated by cancelli. (For diagnosis see Pt. III.) No Jurassic 



representatives. 



Order 3. TREPOSTOMATA, Ulrich. 



Gymnolsema in which the zoarium consists of straight, pris- 

 matic, or cylindrical tubes, growing in thick sheets or masses. 

 Apertures always terminal. Zooecia divided into proximal, im- 

 mature portions, in which the zooacia are thin-walled, and of 

 which the structure is simple; and into distal, mature regions, in 

 which the walls are thickened and diaphragms are numerous. 

 Mesopores occur in many forms. No avicularia or vibracularia, 

 but spines sometimes occur (acanthopores). 



Fam. 1. Ceramoporida. See Pt. III. 

 ,, 2. Heterotrypida. See Pt. III. 

 ,, 3. Amplexoporidce. See Pt. III. 



