Plate 4. 



Pennaria tiarella, page 7. 

 The figures are from camera drawings finished by J. H. Emerton. 



Fig. 1. A very young hydranth showing the filiform tentacles and the most distal capitate 



tentacles appearing first, the capitate in a verticil, x 40. 

 Pig. 2. A somewhat older hydranth with the second verticil of capitate tentacles showing. 



x 40. 

 Pig. 3. A later stage with the capitate tentacles still in verticils, x 40. 

 Pig. 4. A still older hydranth with the filiform tentacles cut away, showing the capitate 



tentacles now in an irregular. arrangement, especially on the proximal part of 



the hydranth. x 40. 



