200 BULLETIN 125, UNITED STATES NATIONAL MUSEUM. 



IDMONEA(?) EXPANSA Ulrich and Bassler. 1904. 



Plate 26, fig. 8. 



1904. Idmonea (?) expansa Ulrich and Bassler, Maryland Geological Survey, Miocene, p. 404, 

 pi. 109, figs. 6-8. 



The original description was as follows: 



Zoarium adnate, beginning with a single zooecium to which others are added rapidly until an 

 irregular flabellate expansion is produced that with further growth becomes more or less lobate. In 

 the older examples the lobes are seen to be due to the development of the zooecia in systems composed 

 of two pinnate series of transverse rows springing alternately from the opposite sides of a zigzag or 

 wavy median line. In the rows the zooecial apertures, wliich are rounded quadrate in shape and 

 elevated, are in contact, with four to si.x in each row and this greater number in about 0.8 mm. The 

 furrows between the rows of apertures are often irregular, and where this in the case the rows themselves 

 are not continuous. When the arrangement is normal the average indth of the furrows is a little less 

 than that of the rows of apertures, allowing about four of the latter to come within the space of 1.0 mm. 

 The grooving margins of the expansions are occupied by numerous crowded angular cells, decreasing 

 in size toward the extreme edge. Zooecial walls minutely porous. 



Occurrence. — Miocene (St. Mary's formation) : Cove Point, Maryland (rare) . 

 Cotypes.— Cut. No. 68744, U.S.N.M. 



Genus CRISINA D'Orbigny, 1852. 



CRISINA? STRIATOPOKA Ulrich and Bassler, 1904. 



Plate 27, figs. 1-4. 



1904. Crisina striatopora Ulrich and Bassler, Bryozoa, Mi«cene, Maryland Geological Survey, 

 p. 406, pi. 118, figs. 1-4. 



Ulrich and Bassler 's original description was as follows: 



Zoarium erect, ramose, probably not exceeding 1 cm. in height, dividing dichotomously at intervals 

 of about 1.5 mm.; branches subovate in cross section, thickest, uniformly convex and traversed longi- 

 tudinally by from sixteen to twenty punctate striae on the reverse side, narrower and carrying alter- 

 nating series of zooecial apertures on the obverse side. Zooecial apertures rarely three usually four 

 in each series, in contact laterally, the inner one of each series largest, most prominent, and subcircuiar 

 the outer one smallest, drawn out distally and apparently grading into the pores lying between the 

 longitudinal ridges of the reverse side. Series of zooecia curving first forward then slightly backward, 

 separated by a deep interspace averaging about 0.2 mm. in width; about five rows in 2.0 mm. Over 

 the basal part of the zoarium the zooecial apertures are covered one after the other by the growth of 

 the striato-punctate dorsal integument. 



In order to properly classify this species thin sections and the nature of the 

 ovicell are necessary. Additional specimens are needed before further studies 

 upon it are made. 



Occurrence. — Miocene (Choptank formation) : Jones Wharf, Maryland (rare). 



Holotype.—CsLt. No. 68745, U.S.N.M. 



