ZOANTHARIA 



Synopsis of the fsosoantkus-species described here. 



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

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

 tionally cell-islets. Number of mesenteries 28 32 bulbosus. 



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

 The polyps are elongated, slightly attached. 



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



nematocysts in the filaments 31 38^ x n 12 ;JL arboresccns. 



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

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



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



b. Elongated, small polyps. 



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

 26 34;* x 10 12 // partly smaller 14^ x 5^. Well developed coenenchyme tube-shaped 

 covering needles of Hexactinellidae (always?) islandicus. 



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

 19 26 [j. x 10 12//, partly smaller 12 14^ X 56^. Cceneuchyme 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. 

 Mesogloea of the body-wall almost homogeneous with very scarce cells. Coenenchyme 

 band-like, branched danicus. 



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

 31 43ju x i2;u, partly smaller 15^ x 7/j. MesogLta of the body-wall contains numerous 

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



Coenenchyme band-like, branched magninsulosus. 



ddd. Number of mesenteries 3840. Specific nematocysts in the filaments partly large 

 41 48 // x 14 iy//, partly smaller 1719^ x 7 /^. Mesogloea of body-wall contains 

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



coenenchyme of small dimensions multinsulosus. 



dddd. Number of mesenteries 3840. Specific nematocysts in the filaments partly large 

 31 40 // x 12 14(19) /*, partly smaller 17 19^ x 7 ft. Mesogloea 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 coenenchyme ingolfi. 



Isozoanthus bulbosus n. sp. 



PI. i, figs, 5, 6. PI. 2, figs. 1416. PI. 6, fig. i. 



Occurrence: 6534'N., 73i / W. 762 Danish fathoms. Bott. temp. 0-8. St. 105 Ingolf Ex. 

 Several specimens. 



