152 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



Genus CYSTISELLA Canu and Bassler, 1917. 



(For description, see Bulletin 106, U. S. National Museum, p. 479.) 



CYSTISELLA AVICULIFERA, new species. ' 



Plate 38, f5g. 8. 



Description. — The zoarium incrusts pebbles or algae. The zooecia are distinct, 



elongate, subelliptical, swollen: the frontal is convex, snaooth or bears an avicularian 



chamber rather large and somewhat salient. The apertura is semicircular and 



placed at the base of a deep peristomie; the peristome is thin, salient, and bears 



two or three orbicular avicularia. The ovicell is large, hyperstomial, convex, 



globular, smooth; it opens into the peristomie by a very large opening placed 



above the operculum. 



,, . T. • . • f?ipe = 0.15-0.18 mm. „ . fiz = 0.65 mm. 



lleasurements. — reristomice ,^ „ ,„ Zooecia , „ ,^ 



l(pg = 0.16mm. [ (2 = 0.40 mm. 



Affinities. — Our micrometric measurements are taken on the marginal zooecia; 

 at the center of the zoarium they are much smaller, the frontal of the zooecia 

 being much reduced there. The ancestrular zooecia appear to be erect as in the 

 Celleporidae; this aspect is deceiving and is occasioned by the presence of small 

 peris tomial avicularia; they are perfectly oriented like the marginal zooecia but 

 much smaller. The relative constancy of the peristomice permits us to utilize the 

 micrometric measurements. The frontal avicularian chamber is much smaller than 

 in the other species of the same genus; but the absence of the areolar pores leaves 

 no doubt as to the exactness of our generic determination. The multiplicity of 

 avicularia on a given species always reveals whether the water was calm or not 

 very agitated. 



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

 (rare) . 



Holotype.— Cat. No. 68659, U.S.N.M. 



Family RETEPORIDAE Smitt, 1867. 



Genus RETEPOKA Imperato, 1599. 



(For description, see Bulletin 106, U. S. National Museum, p. 500.) 



RETEPORA DOVERENSIS Ulrich and Bassler, 1904. 



Plate 23, figs. 11-17. 



1904. Retepora doverejisis Ulrich and Bassler, Maryland Geological Survey, Miocene, p. 422, 

 pi. Ill, figs. 5-7; pi. 115, figs. 1-5. 



The original description follows: 



Zoarium reticulate, fenestrae of variable size, averaging 0.8 mm. long and about 0.4 mm. wide. 

 Branches varj-ing from 0.2 mm. to 1.0 mm. w-ide, usually about 0.6 mm.; reverse solid, the surface 

 generally smooth, occasionally minutely granulose, divided into irregular angular spaces by fine 

 impressed or raised lines that may or may not correspond w-ith the bases of the zooecial walls. Zooecia 

 immersed, with oblique imbricating and slightly flaring mouths, and a narrow notch in the elevated 

 and angular proximal border. The appearance of the celluliferous surface varies greatly in different 

 specimens, the difference being due chiefly to the presence or absence and number of the avicularia 

 and ovicells. The latter appear as bulbous inflations with a slit running from the center to one edge. 

 M-Tien they occur at all it is usually in abundance. Of avicularia there are at least two sets, the larger 

 ones occurring on the front of the zooecia, forming its highest part and causing it to appear inflated. 



