NORTH AMERICAN EARLY TERTIARY BRYOZOA. 303 



Affinities. This species is very interesting in showing that the production 

 of a peristomie and of a spiramen is a phenomenon in intimate connection with the 

 passage of the eggs and the evacuation of the larvae. Jullien 1 believed that the 

 spiramen was in relation with the opening of the operculum and consequently with 

 the hydrostatic system. Here the operculum of the ordinary zooecia operates with- 

 out a spiramen. The function of the latter therefore is problematical, indeed it 

 may be only a pseudo-spiramen. 



The characters of the species are the thick confluent costules and the fact that 

 the ovicelled zooecia only are provided with a spiramen. 



This species differs from Gephyrotes saillans in its more numerous and united 

 costules and in the points of the avicularia which are directed backward. 



Occurrence. Upper Jacksonian (Ocala limestone) : West bank of Sepulga 

 Kiver, Escambia County, Alabama (rare). 



Cotypes.Cat. No. 64030. U.S.N.M. 



GEPHYROTES SPECTABILIS, new species. 



Plate 84, fig. 16. 



Description. The zoarium incrusts shells. The zooecia are distinct, elongated, 

 elliptical, separated by very long interzooecial cavities. The frontal is convex 

 and is formed of six pairs of widely separated costules. Each intercostular slit 

 is followed by a lacuna ; each costule bears a small but prominent lumen pore on 

 the loop and a larger one at the other extremity. The first pair of costules bifurcates 

 to surround the spiramen which opens obliquely above the aperture. The ovicell 

 is embedded in the distal zooecia; it is globular, projecting, transverse, and bears 

 in front a hollow collar; it opens into the peristomie formed by the avicularia 

 and the prominent lamella which bears the spiramen. The two oral avicularia 

 are quite prominent, triangular, oblique, the point directed toward the upper 

 extremity of the zooecial median axis; provided with a calcareous pivot. 



Measurements. External aperture -., 



. 1 13=0.50-0.60 mm. 



ia l?3=0.35-0.40mm. (excluding avicularia). 



Variations. This superb species is perfectly characterized by its cribriform 

 area. The lumen pore of the shield is frequently wanting. The two opposite 

 lacunae are frequently joined to form a small transversal slit. The large inter- 

 zooecial cavities are very irregular in form and size; it is impossible to consider 

 them as avicularia and their function is therefore problematical. 



The marginal zooecia shown in our figure appear to be of young zooecia : they 

 are without spiramen and avicularia, and their aperture is transverse with a con- 

 cave, proximal border. In the junction angles there is a minute pore, probably 

 a small, simple avicularium. 



1 1903, Jullien. Br.vozoaires provenant de campagnee dTHiroiulrllr. p. 74. 



