Aet. XXII — Descriptions of JS T eiv, or Little Known, 

 Polyzoa. 



Part VI. 



By P. H. MacGillivray, M.A., M.R.C.S., F.L.S. 



[Bead 13th December, 1883.] 



Discoporella reticulata, n. sp. Fig. 1. 



Zoarium orbicular, bordered, convex ; cells connate, radiat- 

 ing in uniserial rows of irregular length ; peristome with 

 the outer border produced, pointed, and entire ; centre of 

 zoarium occupied by large shallow cancelli, separated by 

 narrow raised walls ; a single or double row of smaller 

 rounded cancelli between the rows of cells. 



Port Phillip Heads. 



I have only a single specimen of this species, which seems 

 quite distinct from any previously described. The most 

 distinctive character is the number and large size of the 

 shallow cancelli in the centre of the zoarium. There are no 

 spines to be seen in the interior of any of the cells or 

 cancelli. 



Discoporella pristis, n. sp. Fig. 3. 



Zoarium irregular in shape, bordered, adnate or partly 

 free and raised at the edges ; cells irregularly distributed ; 

 mouth elliptical, peristome entire, divided, or usually pro- 

 duced into a long point with a series of fine spines on one or 

 both sides ; interstitial cancelli rounded, irregular in size 

 and distribution, frequently finely denticulate round the 

 orifice. 



Port Phillip Heads. Found also by Mr. J. B. Wilson. 



The distinguishing character of this species is the peculiar 

 development of the peristome, which in many of the cells is 

 produced on one side into *a long pointed process, one or 

 both sides of which is armed with a series of sharp spines 

 or teeth, giving the whole a marked resemblance to the 

 beak of a sawfish. In many cells, where this prolongation is 

 absent, there are several sharp, slender spines round the edge 

 of the mouth. The cancelli are round, usually with the 

 edge denticulate ; but it is frequently difficult in this, as in 

 some other species, to say what are cells without peristome 

 and what cancelli. In some specimens portions of the 

 zoarium are covered by a thin, calcareous, perforated pellicle, 



