110 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



frequently formed in the older colonies. This 

 figure is drawn from a sj^ecimen in the 

 Cambridge Museum. 



Fig. 3. Vertical section through a portion of a colony 

 (semi-diagrammatic) to show the anthocodia 

 in different stages of retraction, the different 

 sizes of the polyps, the general arrangement 

 of the canal system, the position of the 

 spicules, &c. The mesenterial filaments are 

 represented as being in the same plane as the 

 tentacles, which they are not, in order to 

 illustrate certain points in their relations. 

 The following points are illustrated in this 

 figure : 1' represents the fully - expanded 

 anthocodia of a polyp, 2' represents a par- 

 tially retracted anthocodia in which the 

 tentacles are contracted and folded inwards 

 towards the mouth, the body-wall forms a 

 circular fold over the crown of tentacles, 

 3' represents an anthocodia in which the 

 tentacles and stomodaeum have sunk to the 

 level of the general surface of the colony, 

 4' an anthocodia which has sunk below the 

 surface, and 5' an anthocodia completely 

 retracted, the false mouth having closed. It 

 will be noticed that the long (dorsal) mesen- 

 terial filaments are represented as being all 

 on the left side of the polyps. This indicates 

 that the axis of the lobe from which the 

 section was made was on the left side of the 

 drawing. 



Fig. 4. A fully-expanded anthocodia drawn from a 

 living specimen at Plymouth. The bases of 

 the tentacles are extended in a bullate 



