146 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



Measurements. — ^Apertura 



lha = 0.09 mm. (Le = 0.50-0.60 mm. 



Zo = 0.10-0.12 mm. | Z2 = 0.25 nma. 



Affinities. — This species is of tlie group of Smittina trispinosa Johnston, 183S, 

 in all its characters; it differs from it in the size, the form, and the direction of its 

 avicularium. This avicularium is sometimes interzooecial (fig. 2). We are ignor- 

 ant of the causes which result in the variations in size, dhection, and form of the 

 avicularia. These biologic variations are still to be studied. On the ovicelled zooecia 

 the large avicularium is often transformed into two smaller ones (fig. 3). In the 

 interior (fig. 7) the lyrule is laterally accompanied by two kinds of condyles, 

 probably replacing the small cardelles. 



Occurrence. — Pleistocene: Santa Monica (Rustic Canyon), Cahfornia (common) . 



Cotypes.— Cut. No. 68645, U.S.N.M. 



SMITTINA CALIFORNIENSIS Robertson, 1908. 



Plate 37, figs. 7-9. 



1903. Smittia califomiensis Robertson, The incrusting cheilostomatous Bryozoa of the west coast 

 of North America, University of California Publications Zoology, vol. 4, p. 303, pi. 22, 



fig. n. 



^ . ^ f/i,a = 0.12 mm. „ . fL2 = 0.70 mm. 



Measurements. — ^Apertura , . , „ Aooecia , 



^ [ta = 0.12mm. |te = 0.30mm. 



Variations. — We do not know all the variations of Miss Robertson's species; 

 we are therefore not exactly certain of our determination. However, our specimens 

 bear the principal characters. The peristome is little salient; it frequently bears 

 two large lateral lips, leaving between them a false rimule (fig. 7) . We have found 

 some zooecia bearing a large, lateral avicularium; the latter is replaced by two 

 smaller, thin avicularia whose beak is turned toward the bottom (figs. 8, 9,) or 

 indeed one toward the top and the other toward the bottom. The interareolar 

 costules are thin (fig. 7) or very thick (fig. 8) . The interzooecial avicularium bears 

 a rectilinear pivot. The zoarium is bilameUar while that in Miss Robertson's 

 species is incrusting. 



Occurrence. — Pleistocene: Santa Barbara, California (rare). 



Hahitat. — Pacific, off California. ' 



Plesioty pes. —Ca.i. No. 68646, U.S.N.M. 



SMITTINA(?) BREVIS Cana and Busslcr, 1919. 



Plate 2, figs. 20, 21. 



1919. Smiltiriaf brevis Canu and Bassler, Geology and Paleontology of the West Indies, Bryozoa, 

 PuljUcation of the Carnegie Institution of Washington, No. 291, p. 93, pi. 2, fig. 2. 



Description. — The zoarium is bilamellar with fronds somewhat compressed. 

 The zooecia are little distinct, elongate, elliptical; the frontal is convex and very 

 short and it bears below a large salient avicularium with rounded beak. The aper- 

 tura is elliptical and deep. The ovicell is globular, little salient, ornamented by a 

 fragile circular area; it opens into the peris tomie. 



Affinities. — This species is quite unique and difficult to classify. We have put 

 it in Smittina because the ovicell opens into the peristomie formed by the thicken- 



