118 THE VOYAGE OF H.M.S. CHALLENGEK. 



fibres, which end in repeated branches under the ectoderm like those of Zoanthus, but 

 are more numerous, more sharply contoured and waved repeatedly in their course. 

 Besides the branched corpuscles of connective tissue, small and large islands of cells lie 

 in the supporting substance ; I presume that these islands of cells represent the system 

 of cellular cords which are always found in Zoanthus, but are wanting in Ejnzoarithus. 

 At certain points they are prolonged into longish sausage-shaped cords, several of which 

 may also become united into a dendritic figure. In many parts of the ccBnenchyma 

 I still found the remains of a branched vascular system, which formed very small 

 meshes, especially about the endodermal connective tubes. I therefore feel justified 

 in my conjecture that the oval islands of cells are caused by the unsatisfactory state 

 of preservation, and are produced by the disintegration of a system of anastomosing 

 cords. 



A powerful circular muscle lies in the horizontally inverted part of the wall ; it is 

 broad at the beginning of the oral disk and becomes narrower from within outwards. 

 The imperfect state of preservation did not allow me to give any histological descrip- 

 tion of its bundles of fibrillse which run in the mesoderm between the ectoderm and 

 endoderm. I could not make out that it was divided into a larger and a smaller part as 

 in Zoanthus. 



The large size of the individual polyps of Epizoanthus parasiticus renders them 

 admirably suited for dissection by means of knife and scissors. If we cut open the animal 

 longitudinally and spread it out by turning back the upper end of the wall (PI. III. fig. 

 12), we find adjacent to the latter, the double corona of long, filamentous tentacles, 

 the aggregate number of which amounts to seventy or eighty. The tentacles of the inner 

 row alternate with those of the outer. The oral disk extends far down, and is covered 

 with shallow radial furrows corresponding to the tentacles. It is divided by a distinct 

 thickening from the oesophagus, in which our attention is at once attracted to the single 

 oesophageal groove. When spread out the oesophageal groove forms a scutiform plate, 

 separated from the adjacent parts of the oesophagus by longitudinal furrows, and divided 

 by a more distinct median furrow into a right and a left half; it is prolonged far below 

 the lower margin of the oesophagus, so that it is almost twice its length. The triangular 

 lappet formed in this way is likewise divided into two by the prolonged longitudinal 

 furrow, and deeply indented at the end. 



Below the lower margin of the oesophagus there are seen thirty-two to thirty-four septa, 

 the zigzag margins of which are caused by the reproductive organs ; these are macrosepta, 

 the microsepta only becoming visible when the others are folded back. I examined the 

 mutual relations of the two kinds of septa in transverse sections and with essentially the 

 same result as G. v. Koch in Epizoanthus axinellce (Morphol. Jahrb., Bd. vi. p. 359, 1880). 

 Two pairs of directive septa lie at the ends of the sagittal axis, the dorsal pair consisting 

 of microsepta, the ventral of macrosepta ; the latter only reach the oesophagus and are 



