128 A MONOGRAPH OF THE TBRTIAUY POLTZOA OP VICTORIA. 



spaces for the openiniz:s of the zocccia ; thyrostomes little prominent or immersed, 

 tlie peristome helow raised and entire or sinnated, and Avith a prominent rounded or 

 suhconical eminence immediately below the lower margin. Posterior surface 

 strongly longitudinally fibrillatc, the fibrillii; minutely tubercular or granular and 

 the intervening sulci destitute of pores. 



B. 



8. H. involnta, n.sp. PL XIX., fig. 3. 



Zoarium stout, branches irregularly dichotomously divided, slightly convex in 

 front, flat and depressed behind. Anterior surface with strong, sharply-raised 

 longitudinal ridges, between which are the depressions for the zocecia, tlie 

 depressions having a few pores ; the zooecia in the centre irregularly arranged, on 

 tlie margins arranged at regular intervals in transverse rows of one or hvo, the 

 extei-nal much projecting ; peristome in the central zocecia projecting and frecjuently 

 slightly prominent on each side and deficient above ; external zooecia with outer 

 margin of peristome much produced and pointed. Posterior surface flat or slightly 

 depressed, with longitudinal ridges, the broad intervening spaces usually crossed at 

 short intervals by transverse elevations leaving small pits with frequently a pore at 

 the bottom ; margin of branches regularly sinuated by the projection of the lateral 

 zooecia, with a thickened rim running upwards and downwards from the zooecia, 

 usually turned back to form an involuted rim, but occasionally above a zotpeium 

 sending a branch to form one of the dorsal ridges 



C.B. 



A very peculiar and well-marked species. 



9. II. tenuis, n.sp. PI. XIX., fig. 4. 



Branches veiy slender, usually in three series of zooecia in the front. Anterior 

 surface smooth, divided into three series of depressions or furrows by raised smooth 

 margins, the depressions being wider at the orifices of the zocccia ; zooecia with the 

 thyrostomes directed forwards, circular, entire or sinuated at the proximal edge. 

 Posterior surface with wide, flat sulci, with a few raised pores separated by raised 

 crenulated margins. 



Belmont. 



10. U. diffusa, n.sp. PI. XIX., fig. 5. 



Branches long, slender, ii'regularly divided. Anterior surface with very obscure; 

 ridges, granular or transversely tubereulated, numerous j)or(>s usually arranged 

 longitudinally, but except towards the extremities of the branches the zocecial 



