356 
IXVERSAKIA. 
5. Inversaria laminata, nov. 
Diagnosis. 
Zoariiun of stout cylindrical branches. There are no tubercles- 
or external ridges. 
Zooecia with raised peristomes, which arc either iiTcgularly 
arranged or occur in transverse rows. The exposed parts of 
the zooecia are quadrangular, the zooecia being separated by 
straight, parallel sutures. 
Apertures circular or subtiiangular. 
Avicularia with circular aperture and long, spatulate, mandibular 
depression. 
Dimensions. 
Diameter of branch 
Diameter of zooecia 
Diameter of aperture 
External length of avicularium ... 
2-3 mm, 
*3— "o ,, 
•2--3 „ 
Disteibtjtion. 
Chalk : LnclscloAvn, "W.S.'SV. of Rochester ; Dover. 
Figures. 
PI. XVI. Fig. 5a, part of a zoarium, showing the regular 
transverse rows of peristomes at the upper end ; X 6 dia. Fig. 5b, 
part of the same zoarium, where the peristomes have been worn 
flush with the surface ; X 10 dia. Chalk: Ludsdown. Bowerbank 
CoU. D. 3104. 
Ajeinities. 
This species is most nearly allied to I. tuherosa, fi’om which 
it differs by having circular rather than triangular apertures. 
/. laminata, in fact, has the zooecia of the Meliceritites lonsdalei 
type, whereas in I. tuherosa they agree with those of M. compressa. 
LIST OF SPECIMEXS. 
D. 3104. A zoarium (on chalk). Upper? Chalk. Ludsdo’svn. Bowerbank 
Coll. Figd. PL XVI. Fig. 0 . 
D. 4534. A much branched zoarium (in chalk). Upper? Chalk. Dover? 
Bowerbank Coll. 
