REPORT ON THE ANTIPATHARIA. 41 



mesenteries as usual, but do not appear to form specialised semilunar thickenings on eacb 

 side of the mesentery as in Cirripathes, nor such isolated organs as those of Antipathes 

 dichotoma. The sexual cells are usually imbedded in the tissue of the mesentery. 



Antipathes. 



In Antipathes dichotoma the zooids are very large in comparison with the slender 

 sclerobasic axis which forms their support. The elongation of the zooid in the trans- 

 verse axis is not very marked, not so much so as it appears at first sight. This is due 



Fig. 6. Fig. 7. 



Figs. 6 and '.—Antipathes dichotoma. 



Fig. 6. — Vertical (sagittal) section cutting the sclerobasic axis at right angles, passing to one side of the stomodasum. 

 Fig. 7. — Subhorizontal section passing on the left, below, on the right, above, the insertion of a sagittal tentacle. 



to the fact that whereas the lateral tentacles arise from the peristome, those in the 

 sagittal axis are inserted at a considerably lower level, and there is a deep depression of 

 the ectoderm between them and the oral cone. The stomodasum is elongated in the 

 sagittal axis in its upper section, but is not much folded. Below, its diameter becomes 

 reduced, and there is little difference between the transverse and sagittal dimensions. 

 Ten mesenteries are present in the oral cone, and have a similar arrangement to those 

 of Cirripathes. In this portion there is no difference between the primary and secondary 

 mesenteries. A vertical longitudinal section shows that the secondary mesenteries do 

 not extend beyond the oral cone (fig. 6). The section of the ccelenteron corresponding to 



(ZOOL. CHALL. EXP. PART LXXX. 1S89.) LIU 6 



