Mr. A. W. Waters on Australian Bryozoa. 15 



Mucronella prcesta)is, H., the whole front of the peristome is 

 raised ; in M. porosa, H., there seems to be no true mucro ; 

 and in ilf. contorta, B., and ilf. bisinuata, as previously 

 pointed out, we ought not to speak of a mucro. 



In Smittia the oral avicularium may, just as in Porella, be 

 enclosed in the secondary aperture, as seen in some forms of 

 S. Landshorovii ; and, as at present defined, I find myself 

 unable to decide what is PoreUa, though perliaps we shall 

 find other characters uniting together a part of what is now 

 called PoreUa. 



The mandibles of the oral avicularia of a number of this 

 group show a similarity in having a diagonal strengthening 

 chitinous bar from each side of the lucida. We may call 

 this the Smittia Landshorovii type, represented also by 

 PoreUa cervicornis, Ell. & Sol., P. marsupiunij P. Icevis, P. 

 rostrata^ Umhonula verrucosa^ Smittia rigida, Lorenz ; but 

 before we can know the value of this character further com- 

 parisons of simiharly placed avicularia are required. The 

 variation in position, size, and direction of the oral avicularia 

 of some SchizoporeUoij as for instance S. auriculata, must 

 put lis on our guard against hasty conclusions. 



The Eschara cervicornis of Pallas and M. -Ed wards has the 

 oral avicularia within the orifice, and I have therefore called 

 it PoreUa ; but Mr. Hincks would call it Smittia^ and from 

 this I think we may see the artificialness of the genus PoreUa, 

 as at present understood. 



As to the peristomial characters, there is great variety in 

 the genus Smittia, and again in Sc}i{sop)oreUa there is in many 

 species a raised peristome, as, for instance, in SchizoporeUa 

 discoidea, B. ; and in several CeUeporw, as represented by G. 

 graniun, the peristome is tubular above the oral aperture. 

 Though no doubt often useful specifically, peristomial cha- 

 racters do not seem applicable for generic divisions. 



I give a figure of the Smittia which Dr. Jullien would call 

 ExocheUa hngirostris from Cape Horn, as it shows the lyrula 

 and cardellai meeting and enclosing a space, and probably 

 this is similar to the structure of Smittia tricuspis, H., but 

 in the latter the prolongation of the peristome forms a tube 

 on each side. 



Dr. Jullien lias recently also suggested that IllucroneUa 

 should be dropped ; but I am unable to follow him in the way 

 in which he would divide up the group. 



Smittia untspinosa, sp. nov. (PI. III. figs. 1-3.) 

 Zoarium incrustiiig. Zooecia large, quadrate, distinct^ with 



