208 BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 



zooecium ; its opesium is oval, narrowest below, contracted below the pivot. The 

 ovicell is little apparent. 



ORDINARY ZOOKCIA. 



,, . [7(0=0.08 mm. . (Zg=0.24-0.30 mm. 



Measurements. Opesia , ..,- Zooecia 7 _ n 



[70=0.10 mm. [7s=0.20-0.30 mm. 



ORDINARY ONYCHOCELLARIA. 



. (A0n=0.10mm. . Z0w=0.26 mm. 



Opesia 7 Onychocellaria 7 



17on=0.10 mm. wn=0.14 mm. 



MARGINAL ZOOECIA. 



. A0=0.18-0.20 mm. . Lz=OAO mm. 



Opesia L Zooecia 7 ,. on . , 



[70=0.16 mm. [7s=0.30-0.40 mm. 



MARGINAL ONYCHOCELI.AKI A 



. f Aon=0.20 mm. 

 Opesia I Onychocellaria 



I70w.=0.08mm. 



Lon=OA6mm. 

 70n=0.24mm. 



Affinities and variations. In its external aspect this species is only a small 

 Onychocella angulosa; but one important and very characteristic difference is the 

 size of the marginal zooecia of the zoarium. We have expressed these micrometric 

 variations numerically above. 



Although small, the lateral indentations are very constant, even in the mar- 

 ginal zooecia. In this respect the species differs from Onychocella georgiana. 



The ovarian zooecia have a somewhat larger opesium. 



Occurrence. Middle Jacksonian: Wilmington, North Carolina (rare); near 

 Lenuds Ferry, South Carolina (rare) ; Rich Hill, 5$ miles southeast of Knoxville, 

 Georgia (rare). 



Upper Jacksonian (Ocala limestone) : Nine miles north of Ocala, Florida 

 (rare) ; west bank of Sepulga River, Escambia County, Alabama (rare) ; Old 

 Factory, \\ miles above Bainbridge, Georgia (rare). 



Cotypes.C&i. Nos. 63959, 63960, U.S.N.M. 



ONYCHOCELLA DUPLICITER, new species. 



Plate 32, figs. 28-30. 



Description. The zoarium incrusts other bryozoa. The zooecia are hexagonal, 

 elongated, with their mural rims confluent, dimorphous. The cryptocyst is shallow 

 and as long as the opesium ; the opesium is oval, narrowest at the top ; the polypidian 

 convexity occurs only on the small zooecia a; the opesiular indentations are very 

 small and nearly symmetrical. The onychocellarium is narrow, falciform, longer 

 than the zooecia ; its opesium is small, oval, narrowest below. 



Measurements. 



Zooecia (a). Zooecia B. ONYCHOCELLARIA. 



(A0=0.08 mm. f/io=0.14mm. fZon=0.14 mm. 



I IrtpQi n / 



|/o=0.10-0.12 mm. (7,0=0.12 mm. U0 0.06mm. 



. Lz=QM mm. fZs=0.36-0.40 mm. |Z0n=0.50 mm. 



cia 7-s=0.30 mm. 17s=0.28-0.32 mm. 7on=0.30mm. 



