THEONOA, lOCrLARIA. 
27 
LOCULARIA, Hamm, 1881. 
[Bry. mastr. Ob. -Sen. i., Cycl. p. 44.] 
Diagnosis. 
Theonoidae with a simple zoarium attached hy the whole of the 
lower side ; the outline is sickle-shaped or semicircular; the 
posterior margin is low, while the anterior margin is well 
raised. Upper surface covered hy a smooth epizoarial layer. 
The zoarium is divided into compartments by divergent, 
vertical partition walls. 
Zocecia with thin apertures, which open only on the anterior 
margin of the zoarium. The apertures are more or less equal ; 
those on the sides of the partition walls project above those 
in the middle. 
Type Species. 
Locularia semipatina, Hamm. Haastrichtian : Maastncht. 
Aefinities. 
This genus, with its simple subequal zocecia, appears to be 
a member of the Tubulata, with the apertures occurring in a band 
along the anterior margin of the adnate zoarium. It may be 
regarded as a Theonoid, in which the zoarium is divided into 
compartments by laminae like those of Stellocavea \ but its 
resemblance to Stellocavea, due to the laminae, is less important 
than the marginal position of the apertures and the monomorphic 
nature of the zooecia, whereby it is allied to the Theonids. 
UNREPRESENTED SPECIES. 
1. damesii, Hamm, 1881. 
Syn. Locularia damesii, Hamm, 1881. Bry. mastr. Ob. -Sen. i., Cycl. p. 45. 
Char. — Zoarium transversely elongate, slightly sickle- shaped. It becomes 
rapidly thicker to the front, with a steep slope and vertical anterior margin. 
Compartments always completely open, short, and wide. Zooecia raised high 
laterally on the partition wall ; lying in about six horizontal rows, of three to 
six zocecia in each. A small pore under each aperture. 
Distrib. — Senonian — Maastrichtian : Maastricht. 
2. semipatina, Hamm, 1881. 
Syn. Locularia semipatina, Hamm, 1881. Bry. mastr. Ob. -Sen. i., Cycl.p. 44. 
Char. — Zoarium approximately semicircular. It gradually becomes thicker 
towards the front. Compartments comparatively long and narrow ; usually 
contracted by widening of the front border of the partition walls. 
Distrib. — Senonian — Maastrichtian : Maastricht. 
