NORTH AMERICAN EARLY TERTIARY BRYOZOA. 
457 
is not a good generic character, for semicircular avicularian mandibles of the 
Porella type are observed in three genera on the following species : 
Smittina ( Lepralia ) concinna Busk, 1854. 
Smittina ( Smittia ) unispinosa Waters, 1889. 
Umbonula ( Cettepora ) verrucosa Esper, 1791. 
Ramphostomella ( Eschara ) scabra Fabrieius, 1780. 
We prefer to consider the function of calcification clearly distinct on the geno- 
types of the two genera. It is for this reason that Smittina majuscula Nordgaard, 
1905, seems to be a Porella even though a lyrula is present. Likewise Porella gla- 
ciata Waters, 1900, Porella laevis Fleming, 1828, and Porella plana Hincks are true 
Smittina on account of their frontal with pleurocyst, in spite of the presence of 
semicircular mandibles and the absence of lyrula. 
Certain Smittina are ornamented with false tremopores, but in the interior 
areolar pores alone are visible. 
Historical. — Hincks did not indicate a genotype, The first species described 
in his work is Smittia landsborovi Johnson, 1847, but unfortunately this is a quite 
variable species, very difficult to determine and whose synonymy is not yet exactly 
fixed. We prefer to adopt the second species Smittia reticulata MacGillivray 
which has been found fossil in the Miocene. 
In 1903, Norman changed the name of Smittia to Smittina because the former 
was preoccupied in the Diptera. In 1909, Levinsen extended the meaning of the 
genus Smittina to inacceptable limits. Under the same name lie has combined 
two absolutely different genera. . 
With Waters we can accept Norman’s term but in the exact sense fixed by 
Hincks, for Smittina is one of the most natural genera of the family. 
SMITTINA COLLUM, new species. 
Plate 58, figs. 11-17. 
Description. — The zoarium is plurilamellar ; it incrusts shells or algae over large 
surfaces. The zooecia are large, somewhat elongated, distinct, limited by a fur- 
row or by a salient thread; the frontal is smooth, convex, bordered by a row of 
triangular areolae; it is formed of a smooth pleurocyst, placed on an olocyst per- 
forated laterally, often separable. The peristomice is semilunar and bears a short 
rimule-spiramen ; the peristomie visible externally is salient and bears laterally 
an avicularium ; the peristome is thin and sharp ; the lyrula is much imbedded, 
little visible, wide and flat. The ovicell is hyperstomial, placed on the distal 
zooecia, opening largely into the peristomie. The avicularium is straight, tri- 
angular, with pivot, the beak directed above. 
Measurements. — Peristomice 
[ hpe= 0.20 mm. 
Upc=0.12-0.15 mm. 
Zooecia 
/ Z.?=1.00-1.10 mm. 
! /s=0.50 mm. 
Variations. — On one zoarium the zooecia are not regularly arranged; they 
radiate from false ancestrulae forming thus many subcolonies. This phenomenon 
is frequent in the multilamellar zoaria. 
