.„ ZOANTHARIA 



4° 



Synopsis of the Isozoanf/itis-species described here. 



A. Single polyps or small colonies of two specimens with tnbe or groove-shaped ccenenchyme, which is 

 well-developed, but probably unattached. The mesoglcea of the body-wall contains few cells excep- 

 tionally cell-islets. Number of mesenteries 28—32 6/i/bos?ts. 



B. Single polyps or small colonies of densely placed polyps connected by an inconsiderable ccenenchyme. 

 The polyps are elongated, slightly attached. 



a. Mesoglcea of body-wall contains few small cells. Number of mesenteries 32 — 36. Specific 



nematocysts in the filaments 31—38// x 11— 12// arborescens. 



aa. Mesoglcea of body-wall contains numerous, granular, fairly large cells. Mumber of mesenteries 

 34 — 38. Specific nematocysts in the filaments 36 — 53 // x 12/* davisi. 



C. Colonies with large, fairly well-developed ccenenchyme. 



b. Elongated, small polyps. 



c. Number of mesenteries about 34. Specific nematocysts in the filaments partly large 

 26 — 34^ x 10 — 12/i partly smaller 14// x 5//. Well developed ccenenchyme tube-shaped 

 covering needles of Hexactinellidae (always?) islatidiais. 



cc. Number of mesenteries about 30 Specific nematocysts in the filaments partly large 

 IO ,_ 2 6/z x 10— i2ti, partly smaller 12—14// x 5—6//. Ccenenchyme band-like (on Cidaris 



spines, always?) dubius. 



bb. Polyp of moderate length or short. 



d. Number of mesenteries 18 — 22. Specific nematocysts in the filaments 22—26 // x 7 p. 

 Mesoglcea of the body-wall almost homogeneous with very scarce cells. Ceeneuehyme 

 band-like, branched danicus. 



dd. Number of mesenteries about 32. Specific nematocysts in the filaments partly large 

 31—43^ x 12//, partly smaller 15// x 7//. Mesogkca of the body-wall contains numerous 

 small cell-islets and less numerous large cell-islets often fused together to form lacunae. 



Ccenenchyme band-like, branched magninsulosus. 



ddd. Number of mesenteries 38—40. Specific nematocysts in the filaments partly large 

 41—48// x 14—17//, partly smaller 17 — 19// x 7//. Mesoglcea of body-wall contains 

 numerous small cell-islets and scattered large ones. Lacunae-system slightly developed, 



ccenenchyme of small dimensions multinsulosus. 



dddd. Number of mesenteries 38-40. Specific nematocysts in the filaments partly large 

 3 I _40 /i x 12 — 14(19)//, partly smaller 17 — 19^ x 7//. Mesoglcea of body-wall contains 

 numerous, often elongated cells and larger or smaller cell-islets sometimes fused together 

 at the base of the mesenteries. Large, thin ccenenchyme ingolfi. 



Isozoanthus bulbosus 11. sp. 



PI. 1, figs, 5, 6. PI. 2, figs. 14 — 16. PI. 6, fig. 1. 

 Occurrence: 65°34 / N., 7°3i'W. 762 Danish fathoms. Bott. temp. — o-8°. St. 105 Ingolf Ex. 

 Several specimens. 



