PLETHOPOEl. 
229 
appears to me a typical specimen of P. verrucosa, and its occurrence 
and characters suggest that von Hagenow’s ulcerosa and vihicata 
from the Senonian of Scania are both synonyms of this species. 
If this view he established, then the name vihicata has priority • 
but the figures and description were so poor that it is best to leave 
that species as inadeijuately founded. 
LIST OF SPECIMENS. 
D. 3766. A fragment 8 mm. long and 3 mm. in diameter. The areas between 
the apertures are covered by a dense epizoarial layer. Maas- 
trichter Kalk. Maastricht. Gamble CoU. Identified by M. Pergens. 
D. 1343, A forked stem (on slide), 16mm. long and 3-5 mm. in diameter; it is 
hollow in places. Maastrichter Kalk. Maastricht. Vine Coll. 
D. 1342. A stem-fragment, 5 mm. long and from 2j to 3 mm. in diameter. 
Maastrichter Kalk. Maastricht. Vine Coll. 
D. 3776. A fragment, 4mm. long, of a stem 2mm. in diameter; the structure 
is essentially the same as \Vl Zonatula pseudotorquata, and the closure 
of the zooecia is clearly due to the overgrowth of the apertures of the 
oblique zooecia by a calcareous layer, deposited after the death of 
the zooecia. Maastrichter Kalk. Maastricht. Gamble Coll. 
Identified by M. Pergens. 
? D. 3329. A stem, probably of the form of the Ceriopora vihicata of von HagenoAV. 
The apertures occur in the lower part in horizontal rows ; in the 
upper part the apertures are in groups of two or three, and stand 
out in small elevations. Maastrichter Kalk. Maastricht. Old Coll. 
2. Plethopora arbuscula (Filliozat), 1908. 
Synonymy. 
Sparsicytis arbuscula, Filliozat, 1908. Bry. Cret. Vendome : Bull. Soc. geol. 
France, ser. 4, vol. vii. p. 399, pi. xiv. fig. 6. 
Diagnosis. 
Zoarium of thin cylindrical branches, up to 1 mm. in diameter. 
They may be straight or slightly bent. The tufts bearing 
the apertures project for a length of from a third to half 
the diameter of the stems. The apertures are collected in 
oval groups. Apertures crowded, and may be subangular. 
About *06 to *1 mm. in diameter. Mesopores about one-half 
the diameter of the zooecia. 
Distribution. 
Senonian — Coniacian : Villavard (Craie marneuse) ; Les Boches, St. Andre, 
and Villers, Loir-et-Cher (Zone of Crania ignabergensis). 
