748 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
The tubules are more interstitial than adventitious, for they do not perforate 
the ovicell. 
Occurrence . — Lowest Eocene (Bryozoan bed at base of the Aquia formation) : 
Upper Marlboro, Maryland (rare). 
Geological distribution . — Cretaceous (Vincentown) : Vincentown, New Jersey. 
Plesiotypes. — Cat. No. 65457, U.S.N.M. 
Fig. 242. — Genus Crisulipora Robertson, 1910. 
A-C. Crisulipora occidentalis Robertson, 1920. A. Zoarium, natural size. B. An ooecial in- 
ternode, X 20, showing its origin in two zooeeia in whose walls the first chitinous joint (j) oc- 
curs, and the mode of formation of three branches; also, the ooecium ( oe ) distinguished by its 
coarsely punctate wall, with the tubular aperture ( ocst . t.) and circular oeciopore. The tubes 
at the distal extremity of the internode, the proximal portions of which only are shown, give 
rise to another internode. C. A portion of the lower part of a colony showing a rootlet (r) which 
grows long, penetrating masses of other material ; another which is shorter and possesses a hook 
( h ) or process which has laid hold of a grain of sand or a pebble; and a stolonlike process ( sto ) 
which grows horizontally sending up zooeeia at intervals which produced new branches. From 
the first zooecium ( zoe ) there arise two tubes one of which gives rise to a double joint (dj.) 
giving off branches at an angle to each other and hence in different directions. (A-C, after Rob- 
ertson, 1910.) 
