Introduction to Animal Morphology. \ 1 9 



somatic cavities of the polyps extend into the coeno- 

 sarc as a communicating tubular system, into which 

 the mesenteric folds extend. The sex organs develop 

 on these, as in Zoantharia, and craspeda are often 

 present. 



Three families are contained: — i. Cornulariidae — rarely 

 simple (Haimeia with retractile polyps and a simple tube ; 

 Hartea,*with stellate basal, and branched 

 tentacular spicules), generally compound, 

 increasing by basal budding or by stolons ; 

 in the former case, the spicules may be 

 fusiform, or cylindrical, spiny or tuberous, 

 and the polyps retractile (Sympodiumf ), 

 or non retractile (Anthelia) ; the outer 

 layer may be smooth and the polyps re- 

 tractile (Lobularia). The stoloniferous 

 forms may have non-retractile, wart-like 

 calyces and a creeping, thick coenosarc Spicules of Aicyonicte ; 



■' A, I, 0, lelesto Atncana ; c, 



(Sarcodictyum). The polyps may be Muncca granulosa ;(/, ai- 



,, , .•i/T->i' -x cyonium digitatum ; e, Pa- 



tubular, non-retractile (Khizoxenia), or raicyonium eiegans. 

 retractile, ribbed and spiculigerous (Clavularia), or smooth, 

 non-spiculigerous (Cornularia). 2. Telestidae — compound, 

 increasing to a tree-like colony by lateral budding, ex. 

 Telesto. 3. Alcyonidae — lobate or branched masses, formed 

 by lateral budding, often granular on the surface. Alcyo- 

 nium is fleshy, lobate, with retractile polyps on all sides ; 

 Sarcophytum has a discoidal pedicellated polypieroid, barren 

 beneath ; Ammothea has semi-retractile zooids ; Belonella is 

 capitate, with plaited-mouthed zooids ; Xenia has clustered, 

 non-retractile polypes on the ends of the branches of a soft, 

 slightly-branched coenosarc ; Nidalia has a cartilaginous, 

 cylindrical stem, with fusiform spicules, the zooids on the 

 upper surface of a hemispherical head ; Spongodes has a 

 membranous, cellular, outer surface covered by opaque, fusi- 

 form spicules ; Nephthya has a branched, coriaceous, granu- 



* This may be an immature form of Alcyonium ( Wright). 

 t This may belong to Briareacese. 



