BRYOZOAN FAUNA OF VINCENTOWN LIMESAND 41 



much elongated, median. The ancestrula is a small ordinary 

 zooecium. 



Measurements. — 



„ . [Lz = 0.5 mm. ~ . {ho = 0.12 mm. 

 ZooeciurcU , _ . OpesiumK _ ., „ 



I lz = 0A mm. |/<9 = 0.1o mm. 



26 zooecia in 4 sq. mm. 



Affinities. — Our specimens are fragmentary, and we figure the 

 best example to indicate the presence of the genus in American 

 strata, where it previously had not been found, even though it 

 is abundant in the European Cretaceous. 



Occurrence. — Vincentown limesand : Very rare at Noxontown 

 Millpond, Del. 



Holotype.—U.S.'NM. No. 73904. 



Family SETOSELLIDAE Levinsen, 1909 

 SETOSINELLA, new genus 



The ovicell is cassiform, 8 hyperstomial, not closed by the oper- 

 culum. The proximal border of the aperture is limited by a trans- 

 verse, salient trabecula attached to the mural rim (as in Micropora) . 

 The cryptocyst is bounded entirely by the mural rim and bears two 

 lateral opesiules. In each interzooecial angle there is a setiferous 

 avicularium. 



Genotype. — Setosinella proliflca, new species. 



In this genus the zooecial structure is exactly that of Micropora, 

 but the ovicell is hyperstomial and is not closed by the operculum 

 as in Setosella. It appears to us to be cassiform, that is, not placed 

 on the cryptocyst of the distal zooecium and as interzooecial. 



SETOSINELLA PROLIFICA, new species 



Plate 9, Figures 7, 8 



Description. — The zoarium encrusts fragments of shells and other 

 Bryozoa. The zooecia are distinct, separated by a deep furrow, oval, 

 swollen, little elongated; the mural rim is thin, salient; the crypto- 

 cyst is deep, smooth, flat, subcircular, entirely surrounded by the 

 mural rim and by the transverse trabecula. The aperture is ter- 

 minal, semicircular; the peristome is salient and adorned with four 

 hollow spines. On the peristome of many of the zooecia is a distal 

 thickening perforated by a pore or by a transverse slit. 



The ovicell is hyperstomial, not closed by the operculum, globular, 

 smooth, and occurring frequently. The avicularia are placed in the 

 interzooecial angles; they are long, very thin, with two denticles for 



8 In this type of ovicell, the length is added to the zooecial length in measurements. 



