STOitATOPORA. 
5 
Stomatopora regularis, Gabb k Horn, 1862. Mon. Pol. : Journ. Acad. Nat. 
Sci. Phil. ser. 2, vol. y. p. 172, pi. xxi. fig. 63. 
^Stomatopora amphorceformis, Hamm, 1881. Bry. Mastr. Ober-Sen. pt. i. p. 26. 
,, constricta, Pocta, 1892. Mech. Koryc. : Ces. Akad. Pr. Jos. Praze, 
sect. ii. p. 12, pi. i. figs. 7, 8. 
,, rariabilis, Vine, 1892. Add. Cret. Pol. : Proc. Yorks. Geol. Soc. 
vol. xii. pt. 2, p. 150, pi. vi. figs, la, b. 
,, dixoni, pars, Vine, 1893. Cret. Polyz. : Eep. Brit. Assoc. 1892, 
p. 307. 
Diagnosis. 
Zoarium typically forming an irregular network; but in less 
densely growing varieties it consists of irregular, radiating 
tufts, the branches of which dichotomize repeatedly. Young 
zoaria may consist of a single line of zooecia, and in some 
zoaria long, uiibranched series predominate. The branches 
are occasionally biserial in places owing to crowding of the 
zooecia. 
Zooecia usually cylindrical, but varying to subfusiform or 
bottle-shaped ; they vary greatly in dimensions and shape. 
The wall is smooth, punctulate or transversely Avrinkled, and 
it is rarely subcarinate. 
Peristomes generally well raised, sometimes twice as high as 
the diameter of the zooecia. 
Dimensions. 
M. Edwards’ 
B.M. 
type. 
B. 112. 
mm. 
mm. 
Diameter of zooecia -3 
•3 
Length of zooecia *7 
•8 
Diameter of aperture 
(inside measurement) *1 
•1 
B.M. 
B.4245. 
Pergens. 
Var. 
gigantea, 
Pergens. 
Waters. 
mm. 
mm. 
mm. 
mm. 
•6 
•26--5 
•4-’6 
•15 
1-2-2-3 
•5-1 
1-2-1-5 
1 
•12--2 
•08--1 
•12 
•12 
Distribution. 
British : 
Upper Chalk — Zone of JBelemnitella mucronata : Norwich. 
Zone of Actinocamax quadratus ; Highfield and East 
Harnham, near Salisbury. 
Zone of Micraster coranguinum : Hitchin ; Gravesend. 
Hertford ; Houghton, Sussex ; Tong, near Sittingbourne ; 
Bromley and Margate, Kent. 
Middle Chalk — Zones of Micraster coranguinum and M. cortestudinarium : 
Chatham ; Stoke Pit, Guildford. 
Lower Chalk : St. Catherine’s Hill, Guildford. 
Chalk Detritus : Charing, Kent. 
