BRYOZOA FROM AUSTRALIA. 437 



40. MlCROPORELLA MAHTSLT, Aud. 



Only two zooecia from Bird Rock. 



Loc. Living : European Seas, S. America, New Zealand, Australia. 

 Fossil : English Crag and Pliocene of Italy. 



41. Microporella cellulosa, MacG., form Adeona. 



Dictyopora cellulosa, MacGillivray, Trans. Roy. Soc. Vict. 1868. 



Adeona cellulosa, Kirchenpauer, " Ueber die Bryozoen-Gattang 

 Adeona," Jouru. Mus. Godeffroy, 1879, p. 10. 



Dictyopora cellulosa, MacGillivray, Nat. Hist. Yict. decade v. 

 p. 37, pi. 47. fig. 1, & decade vii. pi. lxvi. fig. 1 e. 



Erom the examination of some recent specimens, I am convinced 

 that we should place this with Microporella. Although I was 

 unable to prepare out any opercula, yet sections showed me that 

 the proximal edge of the oral aperture was straight, and there are 

 two contractions near the base of this aperture. The oral aperture 

 is at a slight distance from the surface, and what has been described 

 as a round aperture is really a peristome. 



In recent specimens of M. cellulosa and albida the suboral pore is 

 round ; but in the fossil, though most pores seem to be round, yet 

 there are a few slightly elongated and denticulated. The interior 

 of the shell is hollowed out round the region of the oral pore. 



M. cellulosa is closely related to M . violacea, var. fissa, a species 

 which shows great variation both in the size of the avicularium and 

 of the elevation of the front of the cell. In small pieces, such as 

 the fossils in question, it is very difficult to distinguish between M. 

 cellidosa, M. grisea, and M. cdbida. 



In M. albida, form Adeona, there are large zooecial avicularia 

 near the borders of the fenestras, which have the same form as the 

 smaller avicularia on the front of the zocecium ; and we may ask if 

 this is not a case of the avicularium having enormously developed 

 at the expense of the polypide. Perhaps this may be the way 

 in which many zooecial avicularia have originated. Those who 

 dredge these species should examine to see whether the frequency 

 of these large avicularia depends upon any special condition, such as 

 depth or the nature of the sea-bed. 



Loc. Living : Queen scliff. Eossil : Muddy Creek. 



42. PoRENA COROtfATA, RsS. 



This occurs from Muddy Creek in what I call the b form (Bry. 

 S.W. Yict. p. 334) and from Bird Bock in the c form. 



43. Lepralia pertusa, Esper. 



44. PORELLA MARStJPITJM, MacG. 



Lepralia marsupium, MacG. Trans. Roy. Soc. Vict. 1868, and 

 Nat. Hist, of Yictoria, decade iv. p. 22, pi. 35. fig. 4. 



Porella marsupium, Hincks, Contr. towards Gen. Hist, of Mar. 

 Pol., Ann. & Mag. Nat. Hist. Aug. 1881, pi. i. fig. 6. 



Porella marsupium, MacGillivray, "Descriptions of new or little- 

 known Polyzoa, pt. iii.," Tr. Roy. Soc. Yict., 1882, extra page. 



Q. J. G. S. No. 155. 2 1 



