92 Introduction to Animal Morphology. 



6. Bimeridce hydrocaulus with a perisarc, or rudimental ;. 

 hydranths without an abruptly differentiated hypostome ;, 

 tentacles filiform, in a whorl around the base of the mouth ; 

 sporosacs fixed, ex. Bimeria. 7. Bougainvillida? hydro- 

 caulus with a perisarc ; hydranths as last ; tentacles filiform 

 in a single circlet around the base of the hypostome ; gono- 

 phores phanerocodonic, with four radial canals ; marginal 

 tentacles simple or clustered, ex. Bougainvillea. 8. Kuden- 

 dridcu hydrocaulus as last ; hydranths with an abruptly dif- 

 ferentiated perish >me, and one circlet of simple verticillate 

 tentacles; sporosacs fixed, ex. Kudendrium. 9. Hydractinidx> 

 hydrophyton forming a continuous expansion, its deeper 

 part being a series of freely communicating tubes ofcoenosarc, 

 covered bv a chitinous perisarc ; hydranths, with filiform ver- 

 ticillate tentacles ; sporosacs fixed. In the female spur- 

 there is a rudiniental eetodermal male imagination, and in 

 the male- spumous, the eiuloderm forms rudimental and 

 1 ova, ex. Ilydractinia. 10. Podocorynidae hydro- 

 phyton an adherent expansion of adnate, inosculating tubes, 

 with a chitinous perisarc ; gonophores phanerocodonl 

 Podocoryne. 11. Cladonemidae hydrocaulus developed, in- 

 vested by a perisare ; hydranths with two kinds of tent 

 filiform and capitate; the phanerocodonic gonophores have 

 more than four radial canals, and branched marginal ten- 

 tacles, ex. Cladonema. 12. Nemopsidce hydranths with a 

 proximal and distal circlet of filiform tentacles; planoblasts 

 often blastochemes, with four canals, and clustered dissimilar 

 marginal tentacles, ex. Xemopsis. 13. Pennariadae hydro- 

 caulus developed or none; hydranths with filiform and capitate 

 tentacles ; planoblasts with four canals and 1-4 marginal ten- 

 tacles, ex. Pennaria. 14. Cladocorynidce hydranths with both 

 simple and branched capitate tentacles ; gonosome unknown, 

 ex. Cladocoryne. 15. Myriothelidae hydranth solitary; 

 hydrocaulus none ; tentacles scattered, capitate ; sporosacs on 

 processes from the body of the hydranth, ex. Arum. 16. Cla- 

 vatellidae hydranths with simple, verticillate, capitate ten- 

 tacles ; gonophores are ambulator)- medusae, with undeveloped 

 umbrella, and branching marginal tentacles, ex. Clavatella.. 

 17. Corymorphidae solitary; hydrocaulus with no perisarc ; 



