NORTH AMERICAN LATER TERTIARY AND QUATERNARY BRYOZOA. 
31 
ACANTHODES1A SAVARTI Savigny-Audouin, 1826. 
1812. Flustra savarti Savigny, Description de l’Egypte, Polypes, pi. 10, fig. 10. 
1826. Flustra savarti Audouin, Explication sommaire des planches de Polypes de l’Egypte et de 
la Syrie, p. 240. 
The variations in form and size of this species are extraordinary. We group 
them around some principal forms, but it is evident that the same zoarium may 
exhibit all of them. These forms are as follows: 
1. Forma typica. The opesium is crenulated and elongated; the large zooecia 
have a cryptocyst. The zoarium is incrusting, unilamellar or bilamellar. 
2. Forma texturata. The cryptoc 3 r st is developed on all the zooecia. No 
areal spines. No tubercles. The zoarium is unilamellar and subcylindrical. 
3. Forma reyti. The zooecia are irregular. There are areal spines. No 
cryptoc} T st. No tubercles. The opesium is denticulated and not crenulated. The 
zoarium is unilamellar and subcylindrical. 
4. Forma monilifera. Like typica, but the mural rim is beaded. The zoarium 
is unilamellar and subcylindrical. 
5. Forma delicatula. The cryptocyst is short. There are areal spines. The 
zoarium is bilamellar. 
6. Forma bifoliata. There are areal spines. The opesium is surrounded by 
a sort of salient collar. The zoarium is bilamellar. Tubercles at the angles. 
These various forms and occurrences are noted under the following headings : 
ACANTHODESIA SAVARTI forma TYPICA. 
Plate 11, figs. 1-3. 
The opesium is crenulated and elongated; the large zooecia have a cryptocyst. 
The zoarium is encrusting, unilamellar or bilamellar. 
Our few American specimens, are encrusting. The zooecia are less elongated 
than in the forma monilifera and less spinous than the forma reyti. The micro¬ 
metric variations are very great. The granulations are as beautiful as in the other 
two forms. 
Occurrence.-— Miocene (St. Mary’s formation): Bowler’s wharf, Rappahannock 
River, 18 miles above Lrbana, Middlesex County, Virginia (rare). Miocene (York- 
town formation): Near Suffolk Virginia (rare). Pleistocene: Vero, Florida 
(common). 
Plesiotypes. —Cat. No. 68426, U.S.N.M. 
ACANTHODESIA SAVARTI forma REYTI Canu, 1909. 
1909. Membranipora reyti Canu, Les Bryozoaires fossiles des Terraines du Sud-Ouest de la France; 
III Burdigalien, Bulletin de la Society Geologique de France, ser. 4, vol. 9, p. 443, pi. 15, 
fig. 2. 
1909. Membranipora savarti Canu, Les Bryozoaires fossiles des Terraines du Sud-Ouest de la France; 
III Burdigalien, Bulletin de la Soci6te Geologique de France, ser. 4, vol. 9, p. 444, pi. 15, 
fig. 3. 
Measurements. —Opesia 
\ho = 0.34-0.50 mm. 
I lo = 0.20-0.30 mm. 
Zooecia! 
Lz = 0.50 mm. 
Iz = 0.40 mm. 
