NORTH AMERICAN EARLY TERTIARY BRYOZOA. 77 



Genotype. Electro, pilosa Linnaeus, 1758. Range. Eocene-Recent. 

 The recent species belonging- to this genus are according to Levinsen and 

 Waters: 



Electro, (Flustra) pilosa Linnaeus, 17.">s. 

 Electro, verticcllata Lnmouroux, 1316. 

 Electro. (Membranipora) Ijcllula, Hindis, 1880. 

 Electro, (Flustra) triacantha Lamouroux, 1816. 

 Electro, (Membranipora) distort a Hincks. 1880. 

 Electro, (Tendra) zostc.ricola Nordman. 1839. 

 Electro, (Membraniporo) monostachys Busk, 1852. 

 Electro, (Membranipora) b icolor Hincks, 1880. 

 Electro, (Membranipora) tenrlla Hincks, 1880. 



ELECTRA PARVIMATER, new species. 



Plate 19, figs. 1-3. 



1 Description. The zoarium incrusts oysters; it is uniserial around the ances- 

 trula, but later it develops into multiserial branches. The zooecia are elongated, 

 distinct, pyriform; the gymnocyst is smooth and convex; the mural rim is enlarged 

 at the base, flat, and finely striated. The opesium is large, oval, very finely crenu- 

 lated. The ancestrula is very small. 





.-. . A0=02S mm 1 r/ - \Lz=UAO mm. 



Measurements. Opesium , Zooecium 7 



[ lo=0.l') mm. [43=0.24 mm. 



Affinities. This species belongs to the group of Electra monostachys Busk, 

 1852. It differs from Busk's species in its smaller micrometric dimensions and in 

 the oval form of the zooecia. Moreover the extreme smallness of the ancestrular 

 zooecia hap not been noted in this latter, species. 



Occurrence. Lower Jacksonian (Moodys marl) : 2-J miles north of Robert, 

 Newton County, Mississippi (rare). 



Holotype.Qnt, No. 65S65, U.S.N.M. 



Genus MEMBRANIPORA Blainville, 1834. 



1834, Membranipora BJ.AINVILLE, Manuel d'Actinologie ou de Zoophytologie, p. 447. 



No gymnocyst on the frontal. Two spines at least. 



Genotype. Membranipora mcmbranacea Linnaeus, 1758. Miocene-Recent. 



The living species belonging to this genus are, according to '"Waters: 



Membranipora mcmbranacea Linnaeus, 1758. 



Membranipora danica Levinsen, 1894. 



Membranipora (Flustra) tuberculata Bosc, 1802. 



Membranipora (Flustra) inca D'Orbigny, 1839. 



1 In the citation of measurements, ho is the length and lo the width of the opesia, Lz and te similarly 

 the length and width of the zooecia, Lr and Iv the same for vibraciiliim. Lnn and Jon for the onycho- 

 cellaria, lia and la for the apertura, etc. 



