282 



A. W. WATEES OjS" CHILOSTOMATOTJS BRTOZOA FEOM 



Microporidae seem singular!}^ unfortunate, although, no doubt, Mem- 

 hranijpora must be broken up, not merely because it has become 

 unwield}'-, but because species are included in it in which there are 

 important differences of organization. It seems clearly advisable 

 to include in one family only those forms in which the operculum 

 is fixed in the flexible membrane covering the zooecial area (opesia, 

 Jullien), as in Memhrani^ora angulosa, M. memhrcmacea, &c. ; 

 whereas those like Microjoora imcifera, Busk, which have a " com- 

 plete " operculum placed in a corresponding aperture with a cal- 

 careous border should be placed in another family; but in the 

 ' Eeport ' Am]jMhlestrum capense^ Busk *, a species in which the aper- 

 ture is entirely closed by a thick operculum, is put among the 

 Membraniporidse, a family in which the calcareous aperture is 

 opesial, and not opercular. Then again, under the Microporidae, we 

 find as type the genus Micropora^ which always has an opercular 

 opening ; next, the genus VincuJaria, in which there is an opesia, 

 and in the membranous cover an operculum closely resembling 

 those of Memhranipora angulosa, Ess., Selenaria maculata, &c., 

 while Steganoporella has opercular apertures. 



Both Vincularia and Eschar a are genera that have included widely 

 divergent forms, and on the cylindrical, or erect bilaminar, mode of 

 growth the genera have been based ; therefore it is much to be 

 regretted that they have been revived. Two species of Eschar a are 

 described. E. elegantula, Busk, as to the position of which we may at 

 present withhold judgment ; and E. gracilis. Busk, a species which 

 is found in all stages, from a very delicate Vincularia form to large 

 flat foliaceous growth, and which in this and former papers is called 

 Porina coronata, Ess., a determination based upon direct compari- 

 son with typical P. coronata from the Italian Miocene, with recent 

 specimens sent over by Mr. Haswell, and with a considerable 

 series of Australian fossils. The divisions of the family Escharidae 

 are partly based upon the mode of growth, which is interesting for 

 momentary classiflcation, if we do not forget that the form is often 

 so variable that we might almost call it accidental. This variability 

 can be seen in Crihrilina monoceros, C. terminata, and over a hundred 

 other species. 



Myriozoum is a name given by Donati to the living erect cylindri- 

 cal M. truncatum, which has some structures so different from those 

 of the majority of the Chilostomata, that it is doubtful if it should 

 not be placed in a separate division. The central spongy structure 

 is entirely wanting in the species which Mr. Busk now places under 

 Myriozoum, but probably all the ' Challenger ' species will be found 

 to fall into existing genera. M. honolulense is reaUy in the Heme- 

 scharine stage, and is, in the present and previous papers, called 

 8chizoporeTla phymatopora. M. simplex is known as Gellepora mar- 

 garitacea, Pourtales, but cannot remain with the Celleporce. The 

 name of M. immersum must be changed, as it is very near to a species 

 called Onchopora immersa by Mr. Haswell. 



Mr. Busk proposes a genus Adeonella for forms which have pre- 

 ^ This I have from Algoa Bay. 



