334 



A. W. WATERS ON FOSSIL CHILOSTOMATOUS 



almost becomes part of the peristomial crown. I have only one or 

 two specimens in which there is a slightly projecting tube for this 

 median pore ; and in all other cases it is depressed. In some spe- 

 cimens, besides the small surface-pores, there are larger ones, which 

 have in most cases been avicularia ; and in a few specimens there is 

 a larger spatulate avicnlarium above the oral aperture. 



In a recent specimen in the vertebralis condition, from Darnley 

 Island, I found that a section made from one end showed the central 

 spongy structure with which we are acquainted in the old genus 

 Myriozoum, while a section made from the other showed the cells 

 ranged round the circumference but not meeting in the centre; 

 and a section is thus figured by Mr. Haswell (loc. cit. fig. 10). 



Stoliczka, in his figure, distinctly showed this Myriozoum character; 

 and it is strange to find that he nevertheless placed the species 

 among the Cyclostomata. The slender forms so nearly correspond 

 with Porina borealis, Busk (especially as figured by Smitt in his 

 4 Eloridan Bryozoa,' pi. vi. fig. 144), that, if not the same, they are 

 closely related to it; and the species is also related to Porina 

 filograna, Goldf., figured in d'Orb. Pal. Franc,, pi. 626. figs. 5-10, a 

 common species in the Senonian, and also figured by Hagenow as 

 Eschara Defrancei. Several of Hagenow's species with other names 

 may represent worn specimens, as pointed out by d'Orbigny. 



Although the different conditions pass so gradually from one to 

 another that it is impossible to separate them, it may perhaps be 

 useful to speak of them as condition (a) slender, as fig. 57 ; (b) stout, 

 as vertebralis, figured by Stol. ; (c) more flattened, and showing the 

 quincuncial arrangement more clearly, as in Dieffenbacliiana. 



Log. Eossil : Bartonian, Val di Lonte (Rss.), Montecchio Mag- 

 giore (Rss.), Yienna (JRss.) ; Eerrara di Monte Baldo, Crosaro, Bren- 

 d'ola (all in my coll.) ; Hutchinson's Quarry and Oamaru, New Zea- 

 land, in Lower Eocene of New-Zealand geologists (as e, Woods); 

 Hutchinson's Quarry, Upper Eocene ditto ; Shakespeare Cliff, Upper 

 Miocene ditto (as b) ; Orakei Bay, New Zealand (b & c, Stol.) ; 

 Mount Gambier ( Woods, b & c) ; and common in the Lond. Geol. 

 Soc. coll., and also Eth., junr., coll. from Mount Gambier (as b). 



Living : as b, Holborn Island, Queensland, 20 fathoms (Rasiv.) 9 

 and Darnley Island, Torres Strait, in material sent me by Mr. Brazier, 

 from soundings in 10-30 fathoms. 



41. Porina? column ata, sp. no v. Plate XVIII. fig. 88. 



Zoarium cylindrical, erect, with six cells in a complete series, con- 

 sisting of two rows of three each. Zooecia irregularly oblong, with 

 nearly parallel sides, distinct, separated by a wide rounded ridge, 

 surface rounded, with much-raised acute granulations ; the peristome 

 forms a closed arch over the lower part of the oral aperture ; the 

 opening at the base of this arch is wide and laterally oval ; a large 

 tubular avicularium on each side of the peristome, also raised and 

 continuous with the peristome. Oral aperture rounded below, pro- 

 bably round to saddle-shaped, somewhat contracted above. 



The specimen is in a bad state of preservation ; and diagnosis 



