298 



ERNEST WARREX, 



up of intertwining tubes, wliicli in the aggregate form a thick 

 " woody " stem, 2-3 mm. in diameter, and bearing no trace of 

 internodes or reguhirity of branching. The stems, which bear 

 hydranths, give oif branches more or less alternately with a 

 pinnate tendency (text-fig. 6, A) ; but the arrangement may be 

 very irregular and indefinite. The stems bearing hydranths. 



Text-fig. 6. 



CX23 



Sertiilarella tumida sp. n. A and C. Specimen from Bird 

 Island. B. Specimen from Park Rynie. 



and the branches, are divided by oblique nodes into regular 

 internodes, each carrying a hydrotheca. 



Diameter of terminal branch just below a hydrotheca is 

 about 0'46 mm., and the thickness of the perisarc 35 ju. The 

 hydrocaulus is generally considerably constricted in the 

 region of the node. 



Hydrotheca. — Ovate, divergent, distal end contracted, 

 but slightly expanding immediately around the margin ; 



