NOKTH AMERICAN EARLY TERTIARY BRYOZOA. 617 



ACANTHIONELLA SIMPLEX, new species. 



Plate 2, fig. 6. 



Description. The zoarium is free, bilamellar, bifurcated. The zooecia are 

 indistinctly oriented; the frontal is formed of a thick olocyst bearing a large 

 suborbicular and salient avicularium. The peristome is very deep ; the peristomice 

 is oval and bears on its proximal lip a sort of flat and very prominent lyrula. The 

 ovicell is hardly visible exteriorly; it is hyperstomial and opens widely into the 

 peristomie. 



Affinities. The only specimen found has been figured. We have not been 

 able to study this species in detail; but it was urgent to mention the occurrence 

 of the genus in this stage. 



It differs from Acanthionclla typica Gabb and Horn, 1862. in the presence 

 of a single frontal avicularium (and not 3 or 4) and in its lyrula attached to the 

 peristomice (and not to the apertura). 



It differs from Acanthionella occioporosa in the absence of frontal gibbosities 

 and in the rarity of its frontal avicularia. 



Occurrence. Lowest Eocene (Bryozoan bed at base of Aquia formation) : 

 Upper Marlboro. Maryland (very rare). 



Holotype.V&t. No. 63784, U.S.N.M. 



Genus KLEIDIONELLA Canu and Bassler, 1917. 



1917. Klcidionclla CANU and BASSLER, Synopsis of American Early Tertiary Cheilostome 

 Bryozoa, Bulletin 96, United States National Museum, p. 72. 



The apertura is oval. The frontal is a very thick olocyst. The ovicell is 

 hyperstomial and lodge'd in the olocyst of the distal zooecia; it opens into the 

 peristomie. There are some small and some large interzooecial avicularia. No 

 lyrula. 



Genotype. Kleidionella grandis Canu and Bassler, 1917. 



Range. Claibornian A' r icksburgian. 



The abundance of cumulate zooecia and the absence of lyrula distinguishes 

 this genus from the preceding one, Acanthionella. 



KLEIDIONELLA GRANDIS Canu and Bassler, 1917. 

 Plate 78, figs. 1-17; plate 79, fig. 1. 



1917. KleidioneUa grandis CANU and BASSLEB, Synopsis of American Early Tertiary 

 Cheilostome Bryozoa, Bulletin 96, United States National Museum, p. 72, pi. G, 

 figs 9, 10. 



Description. The zoarium is very large, compressed, formed of bifurcated 

 fronds almost in the same plane, attaining toward the base 2 cm. 5 mm. in width. 

 The zooecia are disposed in two groups, back to back, and inseparable. The 

 axial zooecia, back to back, are oriented; all the other zooecia are cumulate. The 

 superficial zooecia are distinct, urceolate, little raised, very oblique; the frontal 

 is quite convex, smooth, bearing to 3 improminent avicularia with pivot; the 



