718 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
11 . 
12 < 
13< 
14 < 
15< 
16. 
Peristome=0.I8 mm., tubes horn-shaped : Berenicea ingens. 
Peristome=0.20 mm., tubes cylindrical Berenicea benjamini. 
Peristome 0.16 mm 1 Berenicea incondita. 
Peristome smaller 12. 
Zoarium palm-shaped, diehotomously branched and successive Berenicea palmula. 
Zoarium orbicular or irregular 13. 
The zone of growth is very thick ; the tubes are grouped in rows on 
the zoarial margins; P=0.10 mm : Plagioecia divagans. 
Zone of growth little thick or invisible 14. 
Ovicell very long Plagioecia concreta. 
Ovicell short 15. 
Peristome=0.12 mm., tubes claviform Plagioecia clavioedes. 
Peristome=0.08-0.10 mm., tubes bent upward at the extremity Plagioecia brundidgensis. 
Peristome=0.12-0.16 mm., tubes cylindrical Plagioecia botula. 
Peristome=0.10 mm., tubes horn-shaped, rectilinear, not bent up- 
. ward Plagioecia liirta. 
Separation of the peristomes=0.44 mm Plagioecia superposita. 
Separation of the peristomes=0.52 mm ; Plagioecia concreta. 
DESMEPLAGIOECIA, new genus. 
Plagioecia in which the tubes are grouped in fascicles. 
Genotype. — Berenicea lineata MacGillivray, 1885. 
Range. — T 1 1 ron ian- Recent. 
This genus includes the genus Actinopora D’Orbigny, 1852, that is to say, the 
assemblage of species with orbicular zoarium. It is necessary to classify in it also 
Fig. 234. — Desmeplagioecia, new genus. 
A colony of Desmeplagioecia ( Actinopora ) 
lineata MacGillivray, 1885, X 12, in which 
the ovicells form an almost complete ring, 
o, oecidstome. (After Harmer, 1915.) 
certain species of Reticulipora of the group 
Reticulipora obligua D’Orbigny, 1852. We 
include in it also some species of the old 
group of Reptotubigera; these are the in- 
crusting dichotomous forms. We do not 
think that the zoarial dichotomization cor- 
responds to a special function. In spite of 
the very great exterior difference between 
the zoarial forms Actinopora and Reptotu- 
bigera , we class in the same genus all the 
species in which the ovicell is identical and 
which are provided with fascicles. This 
ovicell is transverse and it interrupts or de- 
forms the fascicles just as in Plagioecia it 
obstructs, separates, or deforms the isolated 
tubes. The ovicell is evidently formed be- 
fore the calcification of the neighboring 
tubes. 
The principal species hitherto described are; 
Desmeplagioecia ( Berenicea ) lineata MacGillivray, 1885. Recent. 
Desmeplagioecia ( Pa,votubigera ) gambierensis Waters, 1881. Miocene. 
Desmeplagioecia ( Pavotubigera ) dimidiata Waters, 1884 (not Reuss, 1817). 
Miocene. 
D esmeplagioecia ( Semitubigera ) dollfusi Canu, 1909. Lutetian. 
Desmeplagioecia ( Actinopora ) organisans D’Orbigny, 1851. Cretaceous. 
