600 ANATOilY OF NEOHELIA PORCELLANA (mOSELEY). 



DESCRIPTION OF PLATES LXII. AND LXIII. 



Fig. 1. View of a portion of the colony magnified about four and a half diameters. 

 The colony forms an irregular hollow tube, the horny membrane lining the tube is sho^vTi 

 at the broken ends. The branches on the right side show a tendency to become fused 

 (this tendency is more clearly marked in Moseley's specimen). The granular ridges more or 

 less continuous with the costae are shown as dotted lines. (Del. E. R. Dust.) 



G.R. granular ridges. 

 H.M. horny membrane. 

 P. apertures in tube. 



Fig. 2. View of a portion of the skeleton after the soft parts have been removed — 

 by immersion in a solution of caustic potash followed by careful brushing. 



The 20 septa are arranged in three cycles the primary and secondary of 5 each, and 

 the tertiary in a cycle of 10. 



The costae are more ur less continuous with the septa and bear granular echinulations. 

 There is no columella, but the septa become fused at the bottom of the calicle forming a 

 wall which shuts ofi" the polyp from the remaining portion of the colony. 



1. Primary septa. 



2. Secondary septa. 



3. Tertiary septa. 

 C. Costae. 



G.E. Granular echinulations. 



.S'. Calicle showing irregularity in arrangement of septa. 

 Del. E. R. Dust. 



Fig. 3. Longitudinal section through a polyp. About 70 diameters. The section passes 

 through a tentacle on the left side and between two tentacles, i.e. through a mesentery on 

 the right side. Tiie dotted shaded portion represents the calcareous skeleton, and the 

 ectodermal portion of the stomodaeum is indicated by dark shading. 



Ac. Single acontium with stem much contracted. 



Can. Canal in coenosarc, its communication with the coelenteron of pol}^ is 

 not shown. 



Ca. a. Calcareous skeleton. 



Cy. Calycoblasts. 



Uc. Ectoderm. 



£n. Endoderm. 



Mff. Mesogloea. 



31. Mesentery. 



