BRYOZOAN FAUNA OF VINCENTOWN LIMESAND 65 



stomial, not closed by the operculum, buried in the distal zooecium. 



small, globular, smooth, ornamented with two lateral cicatrices 



placed symmetrically. The ancestrula is a small ordinary zooecium. 



Measurements. — 



. \Lz= 0.6-0.75 mm. . (Aa= 0.09-0.11 mm. 



Zooeciumi, AOC A . Apertura{ 7 



|fe = 0.35-0.4 mm. ^ [?<z=0.1 mm. 



20 zooecia in 4 sq. mm. 



Structure and variations. — We have noted in Stickocados com- 

 positus that the distal peristome is unequally developed in order to 

 form the distal shield. Here in S. mucronatus it is unequally 

 formed ; on the young cells, on the ancestrular cells, and on the ovi- 

 celled zooecia the spines are free; on the adult nonovicelled zooecia 

 only it is formed by the fusion of spines, which thus disappear or 

 leave only faint traces. On the latter zooecia, each aperture appears 

 thus surrounded by a complete thickened peristome. 



On the ancestrular zooecia, the avicularia are separated from the 

 peristome, but on other zooecia they are united to the peristome and 

 separate the proximal shield from the distal shield. The widest 

 zooecia do not always have their costules entirely joined, but they 

 are sometimes separated by two lacunae. Pelmatidia are visible on 

 the well-preserved costules. They are never peripores as in 

 Stickocados compositus. This is the only species of Stickocados in 

 which the ovicells have been observed. 



Occurrence. — Vincentown limesand : Very rare at Vincentown, N.J. 



Holotype.— U.S.N.M. No. 73910. 



Genus DIACANTHOPORA Lang, 1916 



DIACANTHOPORA ABB0TTH Gabb and Horn, 1862 



Figure 1, E ; Plate 14, Figures 4-7 



1862. Escharipora abbottii Gabb and Horn, Journ. Acad. Nat. Sci. Philadelphia, 



ser. 2, vol. 5, p. 149, pi. 20, fig. 33. 

 1922. Diacanthopora abbottii Lang, Catalogue of the Cretaceous Bryozoa in the 



British Museum, vol. 4, pt. 2, p. 233, text fig. 72, pi. 5, fig. 5 (bibliography). 



Description. — The zoarium is free, erect, bilamellar, of large flat 

 or undulated fronds. The zooecia are distinct, separated by a deep 

 furrow, large, elongated, elliptical, bearing all around a strong indi- 

 vidual epicalcification, forming a mural rim much enlarged 

 proximally; the frontal is convex and formed of 14 costules (10 to 

 20) much scattered and united only along the median axis by their 

 distal extremity. The costules are flat, ornamented with proximal 

 pelma and a distal pelmatidia (or a pelma) ; the apertural bar is a 

 concave arch of the same structure as the costules. The apertura 

 is suborbicular, large, terminal, variable; the distal peristome is 

 thin, with four spines on the little calcified zooecia, thick and without 



