Plate I. 



Fig. I. Cainpanidarin in/egra. Part of median longitudinal section showing basal part of hydranth 

 and inner thickening of hydrotheca wall, to the upper side of which the hydranth is attached. 

 No trace of diaphragm whatever. Specimen from Herlo, near Bergen, fixed in picrin-subli- 

 mate-acetic acid (after Rabl), coloured with Delafield's haematoxyline — van Giesson. 

 320/1. 



Fig. 2. Branchivcermnthus reniformis. T\-pe specnneu from "Ingolf St. 28. Nat. size. 



Fig. 3. BraiichioctriiDiflnis reniforinis. H>'dranth seen from below. 21. 



Fig. 4. Branchioceriantlius reniformis. Hsdranth seen from above. The richly folded gastral endoderm 

 distincth' visible through the large oral aperture. 21. 



Fig. 5. Branchioceriantlius reniformis. Primary branch of a blastostyle, showing method of ramifica- 

 tion. The outer, grape-like swellings are close collections of quite small incipient gonophores. 

 30 I 



