414 G. M. MapleNtone : 



very acute ones. Thyrostome orbicular, margins slightly raised ; 

 a long truncated, upright process on one side. 



The long upright truncated processes are not only on the edge 

 of the thyrostomes, but occasionally are present on other por- 

 tions of the surface of the zoarium. Fig. 8a gives a side view, 

 and Fig. 8b is drawn looking down straight upon the specimen, 

 and shows the flat tops of the processes, one of which is on the 

 surface of the zoarium, at a distance from the thyrostomes. In 

 many of the zooecia the perforations are much more numerous 

 than in those figured, making the surface cribriform. 



Hiantopopa corrugata, n. sp. (PI. XXVII., Fig. 9). 



Zoarium encrusting. Zooecia oval, ventricose, immersed ; 

 surface with irregularly shaped hollows and pores, sometimes 

 radiating from the thyrostome. Thyrostome arched above, 

 curved below, with a raised margin. 



The surface very irregularly cribriform, in many instances it 

 consists of raised narrow ribs with deep hollows and pores 

 between. The proximal lip of the thyrostome is often elevated 

 into an umbo. 



Microporella irregularis, n. sp. (PI XXVII. , Fig. 10). 



Zoarium encrusting. Zooecia quadrate, but very irregular in 

 shape; surface very minutely mamillated, sometimes quite 

 smooth. Tliyrostome arched above, straight below ; a reniform 

 covered opening below it. Ooecium globular, smooth, with semi- 

 circular opening and operculum. 



This is near M. malusii, but differs from it in the smooth 

 ooecium and mamilliform surface. One of the zooecia has a row 

 of minute mamillae near the distal end. The specimen is a very 

 small one upon which to found a new species, but I thought 

 it worthy of a place in this paper on account of the peculiar 

 abnormality shown ; the ooecium on the left side of the specimen 

 (as figured) I consider to be the normal form ; the other, which 

 is apparently common to two zooecia, is mis-shapen, has no 

 operculum, and the zooecia adjacent to it do not appear to have 

 anv thyrostomes. 



