Marine Polyzoa of Victoria. 189' 



occasionally in species belonging to other genera, as in 

 Smittia Landshorovii, var. porinoides. Of course both kinds, 

 of pore are essentially different and easily distinguished 

 from the fenestr89 or irregular perforations or depressions, 

 caused by a deficiency in the calcification of the ectocyst, 

 which contribute so much to the ornamentation of many 

 species, and which are frequently filled or even heaped over 

 with calcareous matter. 



The division of the zooecium into two cavities, as in 

 Steganoporella magnilahris, Chlidonia and probably 

 Urceoliioora, is undoubtedly a diflference of great import- 

 ance, although we do not yet understand the real nature of 

 this structure. 



The ooecia deserve more attention than has hitherto been 

 bestowed on them. There can be no doubt that their beino: 

 internal and opening by a special pore, or external and 

 superposed on zooecia, or contained in or formed by modified 

 zooecia, are characters which ought to be considered of 

 considerable importance in a natural classification. 



The arrangement adopted sufficiently explains itself, but 

 there are some points on which a few remarks may be 

 advisable. 



In the Farciminariidce I have included Busk's Farci- 

 viinaria dichotoma as Verrucularia dicliotoma, taking the 

 generic name proposed by Von Suhr, when he supposed it 

 to be an alga. Mr. Hincks has referred it to Flustrella and 

 there is no doubt that the structure of the mouth very much 

 approaches that of the Ctenostomatous genus, and in fact it 

 evidently forms one of the transitionary species between 

 the two sub-orders. Farciminaria proper shews a decided 

 approximation to the same, the presence of ooecia, however, 

 and, in many species, of avicularia clearly placing it among 

 the Cheilostomata ; and I cannot but agree with Mr. Busk 

 in considering that Verrucularia has more affinity with 

 Farchninaria than with any other group. In any case, 

 even if placed among the Ctenostomata, I do not see how it 

 can be included in the genus Flustrella. 



In the Memhraniporidce I have only included forms in 

 which the operculum is incomplete, that is formed by a flap 

 in the membranous front wall without a distinct articulation. 

 The genus Memhrani'pora, as defined in this paper, ought 

 probably to be divided into two; those with the long, 

 incurved spines and the zooecium frequently prolonged 

 below the area, might be separated as Gray's proposed genus 



