XORTH AMERICAN EARLY TERTIARY BRYOZOA. 



469 



opens largeh' into the peristomic. 

 pivot. 



Measurements. Peristomice 



The median avicularium is elliptical, without 



hpe=OAOmm. 



. fZs=0.55-0.60mm. 

 Zooecia | 7 _ 



U3=0.25mm. 



(lpe=OAOmm. 



Affinities. The areolae disappear very easily through alteration in fossiliza- 

 tion. Their absence on the fossils is therefore not a proof of a difference in struc- 

 ture. We do not hesitate to classify this species in Smittina, for the frontal is decep- 

 tive in this genus. Moreover the few specimens figured are the only ones found. 

 It is probable that when better ones are discovered they 

 will be found provided with areolae as usual in the 

 genus. 



Occurrence. Vicksburgian (Marianna lime- 

 stone) : West Bank Conecuh River, Escambia County, 

 Alabama (very rare) ; well in Escambia County, Ala- 

 bama (very rare). 



Cotypes.Cat. No. 64297, U.S.N.M. 



SMITTINA ORBAVICULARIA, new species. 



Plate 61, figs. 1-4. 



Description. The zoarium is unilamellar and 

 creeps over algae. The zooecia are large, elongated, 

 distinct, wide, claviform or turbinate. The frontal is 

 little convex, surrounded by large crowded areolae and 

 short interareolar costules. The peristome is thick and 

 little salient; the peristomice is orbicular; the apertura 

 (in the interior) is semilunar, transverse with a straight 

 or somewhat concave proximal border; the lyrula is 

 visible only in the interior ; it is short and rectangular. 

 The ovicell is small, little salient ; it is formed of a very 

 fragile area surrounded by a collar which is little visi- 

 ble; the ovicell is hyperstomial and opens into the peri- 

 stomie. The avicularium is orbicular, with pivot; it is 

 large, placed eccentrically with at least two orifices for the passage of the muscles 

 which raise the semicircular mandible. 



FIG. 132n. Genus Smittina 



Norman, 1903. 



A, B. Smittina okaroensis 

 Levinsen, 1909. A. Several 

 zooecia, X 55, showing vibra- 

 cula provided with trabecular 

 pivot. B. Operculum, X 100, 

 with form different from the 

 ordinary. (After Levinsen, 

 1909.) 



Measurements. Peristomice [ A^e=0.12 mm. 

 (exterior) \lpe=Q.l2mm. 



. rZs=0.90-1.00mm. 

 Zooecia {^=0.40-0.50mm. 



Apertura j ha=O.W mm. 

 (interior) [Za=0.15mm. 



Affinities. The avicularium of this species resembles that of Smittina 

 okaroensis Levinsen, 1909 (fig. 132w)- dredged off New Zealand. "Its chamber 

 which is separated from the zooecium by a broad, arched line, is provided at the 

 margin with 3-5 pores, and the transverse bar (pivot) which divides the frontal 



