258 



BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



EURITINA TECTA, new species. 

 Plate 5. figs. 1-7. 



Description. The zoarium is free and bilamellate. The zooecia are distinct, 

 very elongate, vaguely oval; the mural rim is thin, thickened laterally, and forms 

 the two lateral facets of the cryptocyst. The cryptocyst is smooth, flat, oblique 

 toward the opesium. The opesium is elongate entire, elliptical, or it may have a 

 proximal border more or less straight. The ovicell is hyperstomial, never closed by 

 the opercular valve, globular, salient, smooth. The primoserial 

 zooecia have special avicularia without pivot, marked with a distal 

 convexity protruding much above the zooecial plane. 



f 0=0.22 mm. 

 Measurements. Upesia {-. 







Zooecia 



=0-12 mm. 

 Zs=0.45-0.50mm. 

 ?s=0.25mm. 



Variations. The lateral grooves are very constant on the 

 fSTfl' ". : -'|6-V| bilamellar zoaria, but on specimens which contain supple- 

 mentary lamellae, the zooecia are devoid of them and appear 

 FIG. 69. Genus to belong to another species (fig. 1). The cryptocyst and 

 Labiopora Lev- ^j ie mura i r i m are formed of very large but very compact 

 olocystal elements (fig. 3). They are a little oriented on the 



a lopora mural rim according to the general rule. The crvptocyst is 



ulata Levmsen, ...... . , . ,. 



1909 Zooecia x often divided into two symmetrical parts by a longitudinal 



23 (After Levin- linear junction (fig. 3). The bottom of the zooecia is the 

 sen, 1909). ordinary olocyst (fig. 4). The interior of the zooecia (figs. 



5, 6, 7) does not correspond at all to the exterior. There is no 

 trace of the grooves in the cryptocyst, and the lower opesial border is much thick- 

 ened as in Aspidostoma Hincks, 1881. 



The primoserial zooecia. quite different in form at the surface, have in the 

 interior a shape exactly identical with the other zooecia, although plainly nar- 

 rower. The exterior distal convexity of these zooecia is very constant and reminds 

 one somewhat of a little roof. Figure 2 shows a regenerated zooecium of quite 

 unusual character. Here a normal zooecium succeeds a "calcified" one. 



Occurrence. Midwayan (Clayton limestone) : One mile west of Fort Gaines, 

 Georgia (common) ; Mabelvale, near Little Rock, Arkansas (common). 



Cotypes.C&t. No. 63807, U.S.N.M. 



Genus LABIOPORA Levmsen, 1909. 



1909. Labiopora LEVINSEN, Morphological and systematic studies on the Cheilostomatous 

 Bryozoa, p. 171. 



No ovicell; distinct raised margins; frontal wall of polypide-tube not quad- 

 rangular and not surrounded by projecting flanges. Polypide-tube bilabiate, on 



