distally. 
becoming more so distally. 
a little too pyriform. 
W. D. Lang—Evolution of Stomatopora. 
23 
The shape of the zocecia is slightly pyriform at first, 
Haime’s figure makes them appear 
The zocecia are yery slightly nbbed throughout. 
The actual measurements of two specimens of this form are given 
in the following table with those of the fragmentary zocecia which 
represent the other forms. 
It will be seen that as far as can be 
British Vine’s Vine’s Gregory’s 
Haime’s | Museum | Michelin’s| figure of | figure of | figure of 
type of | specimen | figure of | S. inter- | S. S. Smithi: 
S. dicho- | B 2287 (8),| Alecto mixta: | Phillipsi : | Cornbrash, 
tomoides: | 2 zoaria: | dichotoma:| Cornbrash, | Cornbrash, Scar- 
e Aalenian, | Aalenian, | Bajocian, | Thrapston. | Thrapston.| borough. 
Postlip. | Crickley. | Bayeux. | Pa=2. | Pa=3. | Px=4. 
Tyre oF BRANCHING. | __ | MALS Males LEN (vais 
At dichotomy 1 I. 180° T. 180° I. 180° 
<a) Tool enor tGos Mtoe 1902 
se i 3 I. 80°-90° | I. 90°-120°| I. 90°-120°|I. 120° | I. 80° 
iy 5S 4 | 1. 60°-S0° | I. 90° It, ABO I, GUE I. 80° I. 60° 
so SS I. 45°-50° Be I. 90° 
ee Fg I. 45°-60° 
NumBer or PreristomEs 
BETWEEN 
EACH DricHotTomy. 
Before dichotomy 1 ? po 2 
Between dichotomies 1 and 2 1 1-2 1 
” ” 255 3 1 1 1 1 
ie ee 1 1 1-2 1 1 1-2 
is Ramat tia" ale 1-2 1 1-2 
” ” BD oq (9 2 | 
Ratio or LENcrTH oF 
Zoacium To BreapTH; 
BreEADtH = 1. 
Before { Zocecium 1 ? “ae 1} 
dichotomy 1 | Pen ? 22 2 
Atidichotomy ll) ... ... 24 24-4 2 
ie 3 3-34 2 22 
36 9b 3 3 3-34 22 24 24 
95 ne + 3h 24-3 2-24 2 24 24 
” ” 5 3 
” ” 6 3 
ia ze = ee a ere |e ee eee 
Cylindrical | Before 1. 
or very 1. 
slightly | Cylindrical. | 
yyriform | 2. F : 
SHAPE oF ZomcIum. Rather ioton 1. | ? Slightly | Pyritorm. | Pyriform. Hippothot: 
pyritorm. 129 ehenaiy eR : ’ form. 
2 slightly) pyritorm. 
pyzitorm. 
3-6 After 1. | 
| pyritorm. | Pyriform. | 
Very . Very || 
slightly | slightly | z | Slightly | 5 
ORNAMENTATION. ribbed ribbed : | ribbed. | : . 
throughout. throughout. | | 
{ 
