266 
EADIOrOBlDiE. 
with which it agrees in haTing a simple zoarium, hut differs by 
having a capitate zoarium. 
It resembles Tholopora in its vertical rows of apertures, but 
that genus has a compound zoarium composed of superimposed 
sub-colonies. It differs from Radiopora, as that genus has a massive 
compound zoarium. 
Trochiliopora humei,^ Gregory, 1909. 
Synonymy. 
Trochiliopora humei, Gregor)’, 1909. New Cret. Bry. : Geol. Mag. dec. t. 
vol. vi. p. 65. 
Diagnosis. 
Zoarium fungiform, composed of a thick disc and stout, blunt 
stem. The diameter of the stem is nearly half that of the 
head. The lower end of the stem is longitudinally grooved, 
with linear pores. In the upper part of the stem the pores 
are irregularly arranged, and the intervening walls are 
reticular. Base of stem discoid. 
The upper surface of the disc is flat ; its central portion is large, 
with numerous irregularly arranged apertures of young 
zooecia and mesopores. Margins vertical or well rounded, and 
marked by radial series of large apertures ; there are three to 
four apertures in each series, and the series are separated by 
lines of cancelli. 
Dimensions. 
mm. 
Height of zoarium ... ... ... . . . ' 11'- 
Diameter of head ... 7x6 
Diameter of stem ... ... ... 2’5 
Diameter of zooecia ... ... '4--5 
Diameter of apertures ... ... ... . . * 2 -• 25 
Disteibution. 
Upper Chalk — Zone of Micraster coranguinum : Gravesend. 
Figijees. 
PI. III. Fig. 2. The type-specimen. Upper Chalk : Gravesend. 
Fig. 2a, from the side ; X 3 dia. Fig. 2h, the same from above ; 
X 3 dia. ? Bowerbank Coll. D. 2995. 
* The species was named in MS. in 1899 in acknowledgment of the value of 
Dr. W. F. Hume’s work on Cretaceous petrology, and his donations of Chalk 
Bryozoa to the Museum. 
