96 HALF AN HOUR WITH CORALLINES. 



the other hand, the male capsules are regularly 

 oval, with four ridges running down them, and 

 about eight spines running in two series on the 

 upper part (Fig. 47). This species, however, unlike 

 the others just described, is tolerably abundant, and 

 seems to have a pretty general distribution. 



The true sertularians have been grouped according 

 to the arrangement of their cells, like the genus 



Fig. 47. 



Diphasia pinaster, a. calycles ; 6. female capsule. 



Diphasia. Two species are very small, and but 

 slightly branched, one having its cells arranged in 

 an opposite manner, with the branches regularly 

 pinnate. This species, Sertularia filicula, is the 

 only one in which this peculiarity occurs. Perhaps 

 the commonest form, and that most likely and most 

 abundantly to be met with by the collector, is the 



