Occurrence of Recent Eeterojpora. By Arthur Wm. Waters. 391 



Mr. Busk explains by considerk^ the septa to represent the 

 remains of hymen-Hke lids, which have been left behind at suc- 

 cessive stages of growth. I havt not found this to be the case in 

 this species or fossil ones examined, but suppose it must occur in 

 other species. 



The pore-tubes can be seen in the transverse sections, Figs. 

 3 and 4 ; in Fig. 4, they are shown passing through the 

 zooecial walls ; this structure is the same as we find in all Cyclo- 

 stomata, and the inner portion of Fig. 4 would represent equally 

 well Idmouea, Hornera, &c., for in all of this sub-order numerous 

 minute pores occur in the walls, as is also shown in the longi- 

 tudinal section, Fig. 2, which may also be considered as a cha- 

 racteristic section of the shell structure of the group. In the 

 Cheilostomata, on the other hand, numerous perforations are 

 exceptional, but in the cell-walls of most are comparatively large 

 disks, called rosette-plates, having one or numerous apparent per- 

 forations. In E. peUicuIata the interior of the zooecial tubes has 

 delicate longitudinal markings, with occasional faint transverse lines 

 of growth (see Fig. 2). 



The external surface can best be studied with a calcined 

 fragment. In a piece thus prepared, the calcareous base of a thin 

 pelhcle is seen to cover nearly all the surface. The zooecial aper- 

 tures are nearly equidistant and have sometimes a thin cover, as is 

 the case with most of the Cyclostomata ; * surrounding each cell are 

 about eight cancelli, covered, as already pointed out, and in these 

 coverings are several perforations round which the white calcareous 

 film is thicker, thus giving the appearance of raised warts, and, in 

 fact, until the organic matter is removed this structure cannot be 

 correctly appreciated. The openings of the cancelli are usually 

 much smaller than the zooecial apertures, though in some cases 

 they are nearly as large. 



I have been unable to identify it with any fossil form, and 

 therefore call it 



Eeteropora 'peUlcidata, nov. 



Zooarium erect, branches cylindrical, frequently dividing dicho- 

 tomously, ends of branches sometimes taper, at others swelling 

 out into a subglobular termination. Zooecia ; parallel tubes, per- 

 forated with minute depressed pores. Zooecial orifices circular, 

 interstitial orifices subcircular, disposed round the zooecial orifices. 

 Surface covered with a thin calcareous and organic pelhcle, cover 

 of cancelli numerously perforated. 



Hab. — The Gulf of Tartary and the neighbourhood of the 

 island of Saghalien and Japan, between the latitudes 41°-46° N., 



* Such covers of the Cyclostomatous Bryozoa are specially worthy of note, for 

 in Polypora and other Cari)oniferoiis fossils belonging to the Fenestellidse similar 

 closures have been pointed out by Mr. John Young. 



