56 BULLETIN" 16 5, UNITED STATES NATIONAL MUSEUM 



We have discovered a similar structure of a protective arch in the 

 Galeopsidae ; but here, as has been remarked by Waters, there is no 

 formation of a spiramen, that is to say a special conduit indispens- 

 able for the movement of the operculum. 



The orifice, visible exteriorly, is then never closed by the oper- 

 culum ; it is a false aperture terminating a peristomie. In the other 

 Bryozoa we have given the name of peristomice to such an orifice. 

 We think that this term could perhaps also be employed for the 

 Cribrimorphs. 



According to the classification of Lang, it would be necessary to 

 create a special genus for Kelestoma simplex. Simple or complex, 

 a protective arch is always a protective arch. Not only do we think 

 it unnecessary to create a new genus, but we feel that M orphosmopora 

 could well be joined with Kelestoma. 



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



Holotype.—U.S.'NM. No. 73917. 



Genus TRICEPHALOPORA Lang, 1916 



TRICEPHALOPORA PROLIFERA Gabb and Horn, 1862 



Figure 1, D ; Plate 13, Figures 1, 2 



1862. Reptescharellina prolifera Gabb and Horn, Journ. Acad. Nat. Sci. Phila- 

 delphia, ser. 2, vol. 5, p. 140, pi. 20, fig. 28. 



1907. Reptescharellina prolifera Ulrich and Bassler, in Weller, Geol. Surv. 

 New Jersey, Paleontology, vol. 4, pp. 167, 346, pi. 25, fig. 2 (bibliography). 



1922. Tricephalopora prolifera Lang, Catalogue of the Cretaceous Bryozoa in 

 the British Museum, vol. 4, pt. 2, p. 74, text fig. 21 (bibliography). 



Description. — The zoarium encrusts free Bryozoa such as Pliophloea 

 sagena and Ooscinopleura digitata. The zooecia are distinct, sep- 

 arated by a deep furrow, little elongated, swollen, capitate; the 

 frontal is very convex and formed of a smooth, thick epicalcification, 

 at the center of which is an elliptical costulated area ; the costules to 

 the number of four are short, radiating, much scattered, united only 

 at their extremity; the apertural bar is of the same nature as the 

 costules but a little thicker. The aperture is invisible, buried at the 

 bottom of the peristomie, covered by a thick arch arising from the 

 two oral avicularia and below which is a wide, elliptical, transverse 

 pseudospiramen. The peristomice is elliptical, transverse, larger on 

 the ovicelled zooecia. The ovicell is hyperstomial, buried in the dis- 

 tal zooecium, not closed by the operculum, large globular, smooth. 

 The two oral avicularia are large, triangular, thin, with a pivot, 

 with the beak pointed and oriented proximally toward the apertural 

 bar. The ancestrula is a small ordinary zooecium. 



Measurements. — 



ry . \Lz= 0.55-0.65 mm. „ . , . \hp=Q.ll mm. 

 Zooecia{ , _ . _ „ Jrenstomice { , r _ . „ 



\lz = 0.4-0.5 mm. [Z^ = 0.17 mm. 



